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&lt;p&gt;&lt;b&gt;Neue Seite&lt;/b&gt;&lt;/p&gt;&lt;div&gt;{{T}}&lt;br /&gt;
[[Category:English]]&lt;br /&gt;
[[Category:Introduction to Differential Calculus]]&lt;br /&gt;
&lt;br /&gt;
{{BR}}&lt;br /&gt;
= Introduction =&lt;br /&gt;
&lt;br /&gt;
Differential calculus is the mathematics of &amp;#039;&amp;#039;&amp;#039;instantaneous change&amp;#039;&amp;#039;&amp;#039;. It gives you tools for describing how quickly a quantity changes at a particular moment and how the graph of a function behaves near a point. Its central idea is the [[English:Derivative|derivative]], which connects algebra, geometry, limits, and real-world rates such as velocity, growth, marginal cost, and changing temperature.&lt;br /&gt;
&lt;br /&gt;
This aiMOOC is designed for &amp;#039;&amp;#039;&amp;#039;Grades 11–13&amp;#039;&amp;#039;&amp;#039;. You should already be comfortable with [[English:Functions|Functions]], coordinate geometry, algebraic manipulation, powers, and basic trigonometry. Familiarity with [[English:Limits|Limits]] is helpful, but the key limit ideas are reviewed here.&lt;br /&gt;
&lt;br /&gt;
By the end of the course, you should be able to explain derivatives conceptually, calculate derivatives from first principles and with standard rules, interpret derivative graphs, solve rate-of-change and optimization problems, and justify your reasoning.&lt;br /&gt;
&lt;br /&gt;
[[File:Tangent line to a curve.svg|500px|frameless|center]]&lt;br /&gt;
&lt;br /&gt;
The image shows the geometric meaning of a derivative: at a chosen point, the derivative gives the slope of the tangent line.&lt;br /&gt;
&lt;br /&gt;
{{#ev:youtube|https://www.youtube.com/watch?v=N2PpRnFqnqY|500|center}}&lt;br /&gt;
&lt;br /&gt;
{{BR}}&lt;br /&gt;
== Why Differential Calculus Matters ==&lt;br /&gt;
&lt;br /&gt;
Many questions ask about change. A car&amp;#039;s speed changes from second to second. A company&amp;#039;s cost changes as production changes. The height of a launched object changes with time. A population may grow faster in one period than in another. Differential calculus turns these situations into mathematical questions about [[English:Rate of change|rates of change]].&lt;br /&gt;
&lt;br /&gt;
An average rate of change compares two points:&lt;br /&gt;
&amp;lt;math&amp;gt;\frac{f(b)-f(a)}{b-a}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
An instantaneous rate of change asks what happens at one point. To define it precisely, you let the second point approach the first point. This limiting process produces the derivative.&lt;br /&gt;
&lt;br /&gt;
{{BR}}&lt;br /&gt;
= Foundations: Slopes, Secants, and Limits =&lt;br /&gt;
&lt;br /&gt;
{{BR}}&lt;br /&gt;
== Average Rate of Change and Secant Lines ==&lt;br /&gt;
&lt;br /&gt;
For a function &amp;lt;math&amp;gt;y=f(x)&amp;lt;/math&amp;gt;, choose two input values &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;x+h&amp;lt;/math&amp;gt;. The corresponding change in output is &amp;lt;math&amp;gt;f(x+h)-f(x)&amp;lt;/math&amp;gt;. The slope of the [[English:Secant line|secant line]] through the two graph points is&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;\frac{f(x+h)-f(x)}{h}&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
This expression is called a &amp;#039;&amp;#039;&amp;#039;difference quotient&amp;#039;&amp;#039;&amp;#039;. It measures average change over an interval of width &amp;lt;math&amp;gt;h&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
[[File:Secant-calculus.svg|500px|frameless|center]]&lt;br /&gt;
&lt;br /&gt;
{{BR}}&lt;br /&gt;
== From Secant to Tangent ==&lt;br /&gt;
&lt;br /&gt;
To obtain the slope at a single point, make &amp;lt;math&amp;gt;h&amp;lt;/math&amp;gt; approach zero. The second point moves toward the first, and the secant line approaches the [[English:Tangent|tangent line]] when the relevant limit exists.&lt;br /&gt;
&lt;br /&gt;
[[File:Tangent animation.gif|500px|frameless|center]]&lt;br /&gt;
&lt;br /&gt;
The animation visualizes a central idea of calculus: the tangent slope is not found by setting &amp;lt;math&amp;gt;h=0&amp;lt;/math&amp;gt; in the difference quotient. Doing that would create division by zero. Instead, you examine the value approached as &amp;lt;math&amp;gt;h&amp;lt;/math&amp;gt; tends to zero.&lt;br /&gt;
&lt;br /&gt;
[[File:First principles differentiation demo.svg|500px|frameless|center]]&lt;br /&gt;
&lt;br /&gt;
{{BR}}&lt;br /&gt;
== The Derivative from First Principles ==&lt;br /&gt;
&lt;br /&gt;
The derivative of &amp;lt;math&amp;gt;f&amp;lt;/math&amp;gt; at &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt; is defined by&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;f&amp;#039;(x)=\lim_{h\to 0}\frac{f(x+h)-f(x)}{h}&amp;lt;/math&amp;gt;,&lt;br /&gt;
&lt;br /&gt;
provided the limit exists.&lt;br /&gt;
&lt;br /&gt;
For example, let &amp;lt;math&amp;gt;f(x)=x^2&amp;lt;/math&amp;gt;:&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;\begin{aligned}&lt;br /&gt;
f&amp;#039;(x)&lt;br /&gt;
&amp;amp;=\lim_{h\to 0}\frac{(x+h)^2-x^2}{h}\\&lt;br /&gt;
&amp;amp;=\lim_{h\to 0}\frac{2xh+h^2}{h}\\&lt;br /&gt;
&amp;amp;=\lim_{h\to 0}(2x+h)\\&lt;br /&gt;
&amp;amp;=2x.&lt;br /&gt;
\end{aligned}&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
So the derivative of &amp;lt;math&amp;gt;x^2&amp;lt;/math&amp;gt; is &amp;lt;math&amp;gt;2x&amp;lt;/math&amp;gt;. At &amp;lt;math&amp;gt;x=3&amp;lt;/math&amp;gt;, the tangent slope is &amp;lt;math&amp;gt;f&amp;#039;(3)=6&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
{{#ev:youtube|https://www.youtube.com/watch?v=rAof9Ld5sOg|500|center}}&lt;br /&gt;
&lt;br /&gt;
{{BR}}&lt;br /&gt;
= Understanding the Derivative =&lt;br /&gt;
&lt;br /&gt;
{{BR}}&lt;br /&gt;
== Geometric Interpretation ==&lt;br /&gt;
&lt;br /&gt;
Geometrically, &amp;lt;math&amp;gt;f&amp;#039;(a)&amp;lt;/math&amp;gt; is the slope of the tangent line to &amp;lt;math&amp;gt;y=f(x)&amp;lt;/math&amp;gt; at &amp;lt;math&amp;gt;x=a&amp;lt;/math&amp;gt;. The tangent line gives the best local linear approximation to a differentiable curve near that point.&lt;br /&gt;
&lt;br /&gt;
The tangent line at &amp;lt;math&amp;gt;x=a&amp;lt;/math&amp;gt; has equation&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;y-f(a)=f&amp;#039;(a)(x-a)&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
This equation is useful when you need a simple linear model near a known point.&lt;br /&gt;
&lt;br /&gt;
[[File:Derivative with tangent.svg|500px|frameless|center]]&lt;br /&gt;
&lt;br /&gt;
{{BR}}&lt;br /&gt;
== Rate-of-Change Interpretation ==&lt;br /&gt;
&lt;br /&gt;
If &amp;lt;math&amp;gt;s(t)&amp;lt;/math&amp;gt; gives position as a function of time, then&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;v(t)=s&amp;#039;(t)&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
is instantaneous velocity. Differentiating again gives&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;a(t)=v&amp;#039;(t)=s&amp;#039;&amp;#039;(t)&amp;lt;/math&amp;gt;,&lt;br /&gt;
&lt;br /&gt;
the instantaneous acceleration.&lt;br /&gt;
&lt;br /&gt;
The same structure appears in other subjects. If &amp;lt;math&amp;gt;C(q)&amp;lt;/math&amp;gt; is cost as a function of quantity, then &amp;lt;math&amp;gt;C&amp;#039;(q)&amp;lt;/math&amp;gt; is marginal cost. If &amp;lt;math&amp;gt;P(t)&amp;lt;/math&amp;gt; is a population model, then &amp;lt;math&amp;gt;P&amp;#039;(t)&amp;lt;/math&amp;gt; describes its instantaneous growth rate.&lt;br /&gt;
&lt;br /&gt;
{{BR}}&lt;br /&gt;
== Derivative as a Function ==&lt;br /&gt;
&lt;br /&gt;
A derivative is often itself a function. If &amp;lt;math&amp;gt;f(x)=x^2&amp;lt;/math&amp;gt;, then &amp;lt;math&amp;gt;f&amp;#039;(x)=2x&amp;lt;/math&amp;gt;. The original function tells you the output value; the derivative function tells you the local slope at each input where the derivative exists.&lt;br /&gt;
&lt;br /&gt;
[[File:Graphical of x 2.png|500px|frameless|center]]&lt;br /&gt;
&lt;br /&gt;
You can read qualitative information from the sign of the derivative:&lt;br /&gt;
# If &amp;lt;math&amp;gt;f&amp;#039;(x)&amp;gt;0&amp;lt;/math&amp;gt; on an interval, &amp;lt;math&amp;gt;f&amp;lt;/math&amp;gt; is increasing there.&lt;br /&gt;
# If &amp;lt;math&amp;gt;f&amp;#039;(x)&amp;lt;0&amp;lt;/math&amp;gt; on an interval, &amp;lt;math&amp;gt;f&amp;lt;/math&amp;gt; is decreasing there.&lt;br /&gt;
# If &amp;lt;math&amp;gt;f&amp;#039;(x)=0&amp;lt;/math&amp;gt;, the point may be a local maximum, local minimum, or another stationary point.&lt;br /&gt;
&lt;br /&gt;
A zero derivative alone does not prove that a point is a maximum or minimum. You need additional information, such as a sign change in &amp;lt;math&amp;gt;f&amp;#039;&amp;lt;/math&amp;gt; or a suitable second-derivative test.&lt;br /&gt;
&lt;br /&gt;
{{BR}}&lt;br /&gt;
= Differentiability and Continuity =&lt;br /&gt;
&lt;br /&gt;
A function is &amp;#039;&amp;#039;&amp;#039;differentiable at a point&amp;#039;&amp;#039;&amp;#039; if its derivative exists there. Differentiability is stronger than continuity: if a function is differentiable at a point, then it is continuous there. The reverse is not always true.&lt;br /&gt;
&lt;br /&gt;
For example, &amp;lt;math&amp;gt;f(x)=|x|&amp;lt;/math&amp;gt; is continuous at &amp;lt;math&amp;gt;x=0&amp;lt;/math&amp;gt;, but it is not differentiable there because the left-hand slope and right-hand slope do not agree.&lt;br /&gt;
&lt;br /&gt;
Derivatives can fail to exist at corners, cusps, vertical tangents, discontinuities, or points where the necessary difference-quotient limit does not exist.&lt;br /&gt;
&lt;br /&gt;
{{BR}}&lt;br /&gt;
= Core Differentiation Rules =&lt;br /&gt;
&lt;br /&gt;
Using the limit definition every time would be inefficient. Standard differentiation rules let you calculate derivatives quickly while preserving the meaning established by the limit definition.&lt;br /&gt;
&lt;br /&gt;
{{BR}}&lt;br /&gt;
== Constant, Power, Sum, and Difference Rules ==&lt;br /&gt;
&lt;br /&gt;
For a constant &amp;lt;math&amp;gt;c&amp;lt;/math&amp;gt;:&lt;br /&gt;
&amp;lt;math&amp;gt;\frac{d}{dx}(c)=0&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
For suitable powers:&lt;br /&gt;
&amp;lt;math&amp;gt;\frac{d}{dx}(x^n)=nx^{n-1}&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
For differentiable functions &amp;lt;math&amp;gt;f&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;g&amp;lt;/math&amp;gt;:&lt;br /&gt;
&amp;lt;math&amp;gt;(f+g)&amp;#039;=f&amp;#039;+g&amp;#039;&amp;lt;/math&amp;gt;&lt;br /&gt;
and&lt;br /&gt;
&amp;lt;math&amp;gt;(f-g)&amp;#039;=f&amp;#039;-g&amp;#039;&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
Example:&lt;br /&gt;
&amp;lt;math&amp;gt;\frac{d}{dx}(4x^5-3x^2+7)=20x^4-6x&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
{{BR}}&lt;br /&gt;
== Product Rule ==&lt;br /&gt;
&lt;br /&gt;
For &amp;lt;math&amp;gt;y=f(x)g(x)&amp;lt;/math&amp;gt;,&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;y&amp;#039;=f&amp;#039;(x)g(x)+f(x)g&amp;#039;(x)&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
A common error is to multiply the derivatives. In general, &amp;lt;math&amp;gt;(fg)&amp;#039;\neq f&amp;#039;g&amp;#039;&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
Example:&lt;br /&gt;
&amp;lt;math&amp;gt;\frac{d}{dx}(x^2\sin x)=2x\sin x+x^2\cos x&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
{{#ev:youtube|https://www.youtube.com/watch?v=79ngr0Bur38|500|center}}&lt;br /&gt;
&lt;br /&gt;
{{BR}}&lt;br /&gt;
== Quotient Rule ==&lt;br /&gt;
&lt;br /&gt;
For &amp;lt;math&amp;gt;y=\frac{f(x)}{g(x)}&amp;lt;/math&amp;gt;, where &amp;lt;math&amp;gt;g(x)\neq 0&amp;lt;/math&amp;gt;,&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;y&amp;#039;=\frac{f&amp;#039;(x)g(x)-f(x)g&amp;#039;(x)}{[g(x)]^2}&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
Example:&lt;br /&gt;
&amp;lt;math&amp;gt;\frac{d}{dx}\left(\frac{x^2+1}{x}\right)=\frac{2x\cdot x-(x^2+1)}{x^2}=\frac{x^2-1}{x^2}&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
{{BR}}&lt;br /&gt;
== Chain Rule ==&lt;br /&gt;
&lt;br /&gt;
The [[English:Chain rule|chain rule]] differentiates composite functions. If &amp;lt;math&amp;gt;y=f(g(x))&amp;lt;/math&amp;gt;, then&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;\frac{dy}{dx}=f&amp;#039;(g(x))g&amp;#039;(x)&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
Example:&lt;br /&gt;
&amp;lt;math&amp;gt;\frac{d}{dx}(3x^2+1)^5=5(3x^2+1)^4\cdot 6x=30x(3x^2+1)^4&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
You can think of this as differentiating the outer function while keeping the inner function in place, then multiplying by the derivative of the inner function.&lt;br /&gt;
&lt;br /&gt;
{{#ev:youtube|https://www.youtube.com/watch?v=0T0QrHO56qg|500|center}}&lt;br /&gt;
&lt;br /&gt;
{{BR}}&lt;br /&gt;
== Selected Elementary Derivatives ==&lt;br /&gt;
&lt;br /&gt;
Useful derivatives include:&lt;br /&gt;
# &amp;lt;math&amp;gt;\frac{d}{dx}(\sin x)=\cos x&amp;lt;/math&amp;gt;&lt;br /&gt;
# &amp;lt;math&amp;gt;\frac{d}{dx}(\cos x)=-\sin x&amp;lt;/math&amp;gt;&lt;br /&gt;
# &amp;lt;math&amp;gt;\frac{d}{dx}(e^x)=e^x&amp;lt;/math&amp;gt;&lt;br /&gt;
# &amp;lt;math&amp;gt;\frac{d}{dx}(\ln x)=\frac{1}{x}&amp;lt;/math&amp;gt; for &amp;lt;math&amp;gt;x&amp;gt;0&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
These formulas combine with the product, quotient, and chain rules to differentiate many functions encountered in upper-secondary mathematics.&lt;br /&gt;
&lt;br /&gt;
{{BR}}&lt;br /&gt;
= Higher Derivatives and Curve Behavior =&lt;br /&gt;
&lt;br /&gt;
The derivative of a derivative is the &amp;#039;&amp;#039;&amp;#039;second derivative&amp;#039;&amp;#039;&amp;#039;, written &amp;lt;math&amp;gt;f&amp;#039;&amp;#039;(x)&amp;lt;/math&amp;gt; or &amp;lt;math&amp;gt;\frac{d^2y}{dx^2}&amp;lt;/math&amp;gt;. It measures how the first derivative changes.&lt;br /&gt;
&lt;br /&gt;
When &amp;lt;math&amp;gt;f&amp;#039;&amp;#039;(x)&amp;gt;0&amp;lt;/math&amp;gt;, the graph is locally concave upward. When &amp;lt;math&amp;gt;f&amp;#039;&amp;#039;(x)&amp;lt;0&amp;lt;/math&amp;gt;, it is locally concave downward. A point where concavity changes is called an [[English:Inflection point|inflection point]].&lt;br /&gt;
&lt;br /&gt;
For motion:&lt;br /&gt;
# Position is &amp;lt;math&amp;gt;s(t)&amp;lt;/math&amp;gt;.&lt;br /&gt;
# Velocity is &amp;lt;math&amp;gt;s&amp;#039;(t)&amp;lt;/math&amp;gt;.&lt;br /&gt;
# Acceleration is &amp;lt;math&amp;gt;s&amp;#039;&amp;#039;(t)&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
Higher derivatives appear in mechanics, numerical methods, Taylor approximations, signal analysis, and models of changing systems.&lt;br /&gt;
&lt;br /&gt;
{{BR}}&lt;br /&gt;
= Applications of Differential Calculus =&lt;br /&gt;
&lt;br /&gt;
{{BR}}&lt;br /&gt;
== Tangent-Line Approximation ==&lt;br /&gt;
&lt;br /&gt;
Near &amp;lt;math&amp;gt;x=a&amp;lt;/math&amp;gt;, a differentiable function can be approximated by&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;f(x)\approx f(a)+f&amp;#039;(a)(x-a)&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
For &amp;lt;math&amp;gt;f(x)=\sqrt{x}&amp;lt;/math&amp;gt; near &amp;lt;math&amp;gt;a=4&amp;lt;/math&amp;gt;, you have &amp;lt;math&amp;gt;f(4)=2&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;f&amp;#039;(4)=\frac14&amp;lt;/math&amp;gt;. Therefore&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;\sqrt{x}\approx 2+\frac14(x-4)&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
For &amp;lt;math&amp;gt;x=4.1&amp;lt;/math&amp;gt;, this gives &amp;lt;math&amp;gt;\sqrt{4.1}\approx 2.025&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
{{BR}}&lt;br /&gt;
== Optimization ==&lt;br /&gt;
&lt;br /&gt;
Many optimization problems ask you to maximize or minimize a quantity. A typical strategy is:&lt;br /&gt;
# Define the quantity to optimize as a function.&lt;br /&gt;
# Determine the relevant domain.&lt;br /&gt;
# Differentiate the function.&lt;br /&gt;
# Find critical points where the derivative is zero or undefined within the domain.&lt;br /&gt;
# Compare candidates, including relevant endpoints, and interpret the result.&lt;br /&gt;
&lt;br /&gt;
Example: If a rectangle has perimeter &amp;lt;math&amp;gt;20&amp;lt;/math&amp;gt;, write one side as &amp;lt;math&amp;gt;x&amp;lt;/math&amp;gt; and the other as &amp;lt;math&amp;gt;10-x&amp;lt;/math&amp;gt;. Its area is&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;A(x)=x(10-x)=10x-x^2&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
Then &amp;lt;math&amp;gt;A&amp;#039;(x)=10-2x&amp;lt;/math&amp;gt;. Setting &amp;lt;math&amp;gt;A&amp;#039;(x)=0&amp;lt;/math&amp;gt; gives &amp;lt;math&amp;gt;x=5&amp;lt;/math&amp;gt;, so the maximum-area rectangle is a square with side length &amp;lt;math&amp;gt;5&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
{{BR}}&lt;br /&gt;
== Motion and Instantaneous Change ==&lt;br /&gt;
&lt;br /&gt;
Suppose &amp;lt;math&amp;gt;s(t)=t^3-6t^2+9t&amp;lt;/math&amp;gt; gives position. Then&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;v(t)=3t^2-12t+9&amp;lt;/math&amp;gt;&lt;br /&gt;
&lt;br /&gt;
and&lt;br /&gt;
&lt;br /&gt;
&amp;lt;math&amp;gt;a(t)=6t-12&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
You can use these derivatives to identify when the object is moving forward or backward, when it is momentarily at rest, and how its velocity is changing.&lt;br /&gt;
&lt;br /&gt;
{{#ev:youtube|https://www.youtube.com/watch?v=9vKqVkMQHKk|500|center}}&lt;br /&gt;
&lt;br /&gt;
{{BR}}&lt;br /&gt;
= Historical Perspective =&lt;br /&gt;
&lt;br /&gt;
Modern calculus emerged in the seventeenth century. [[English:Isaac Newton|Isaac Newton]] and [[English:Gottfried Wilhelm Leibniz|Gottfried Wilhelm Leibniz]] developed major parts of calculus independently. Newton often framed change using quantities in motion, while Leibniz introduced influential notation such as &amp;lt;math&amp;gt;dy/dx&amp;lt;/math&amp;gt;. Their work built on earlier ideas about tangents, areas, infinite processes, and rates of change.&lt;br /&gt;
&lt;br /&gt;
[[File:Portrait of Sir Isaac Newton, 1689.jpg|320px|frameless|center]]&lt;br /&gt;
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[[File:Gottfried Wilhelm Leibniz.jpg|320px|frameless|center]]&lt;br /&gt;
&lt;br /&gt;
The modern limit-based foundation of calculus was developed more rigorously in later centuries. Today, derivatives are central across mathematics, physics, engineering, economics, computer science, biology, and many other fields.&lt;br /&gt;
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= Common Misconceptions and Study Strategies =&lt;br /&gt;
&lt;br /&gt;
&amp;#039;&amp;#039;&amp;#039;Misconception 1:&amp;#039;&amp;#039;&amp;#039; A derivative is only a formula. In fact, it is simultaneously a limit, a slope, a local rate of change, and a function.&lt;br /&gt;
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&amp;#039;&amp;#039;&amp;#039;Misconception 2:&amp;#039;&amp;#039;&amp;#039; &amp;lt;math&amp;gt;dy/dx&amp;lt;/math&amp;gt; should always be treated as an ordinary fraction. In introductory single-variable calculus, it is best understood as derivative notation arising from a limiting ratio, even though the notation can be manipulated meaningfully in many later contexts.&lt;br /&gt;
&lt;br /&gt;
&amp;#039;&amp;#039;&amp;#039;Misconception 3:&amp;#039;&amp;#039;&amp;#039; If &amp;lt;math&amp;gt;f&amp;#039;(a)=0&amp;lt;/math&amp;gt;, then &amp;lt;math&amp;gt;a&amp;lt;/math&amp;gt; must be a maximum or minimum. A horizontal tangent can also occur without an extremum.&lt;br /&gt;
&lt;br /&gt;
&amp;#039;&amp;#039;&amp;#039;Misconception 4:&amp;#039;&amp;#039;&amp;#039; Continuity guarantees differentiability. A continuous graph can still have a corner or cusp.&lt;br /&gt;
&lt;br /&gt;
A strong study routine combines four representations: formula, graph, table, and verbal interpretation. When you calculate a derivative, ask what its sign, size, and units mean in the original situation.&lt;br /&gt;
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= Interactive Tasks =&lt;br /&gt;
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{{BR}}&lt;br /&gt;
== Quiz: Test Your Knowledge ==&lt;br /&gt;
&lt;br /&gt;
{{MC}}&lt;br /&gt;
&lt;br /&gt;
&amp;#039;&amp;#039;&amp;#039;What does the derivative of a position function represent?&amp;#039;&amp;#039;&amp;#039;&lt;br /&gt;
(Instantaneous velocity)&lt;br /&gt;
(!Average position)&lt;br /&gt;
(!Total distance)&lt;br /&gt;
(!Constant acceleration)&lt;br /&gt;
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{{E}}&lt;br /&gt;
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{{MC}}&lt;br /&gt;
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&amp;#039;&amp;#039;&amp;#039;Which process defines a derivative from first principles?&amp;#039;&amp;#039;&amp;#039;&lt;br /&gt;
(Taking the limit of a difference quotient)&lt;br /&gt;
(!Substituting zero directly into a denominator)&lt;br /&gt;
(!Multiplying two average rates)&lt;br /&gt;
(!Finding the area under a curve)&lt;br /&gt;
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{{E}}&lt;br /&gt;
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{{MC}}&lt;br /&gt;
&lt;br /&gt;
&amp;#039;&amp;#039;&amp;#039;What is the derivative of x to the fourth power?&amp;#039;&amp;#039;&amp;#039;&lt;br /&gt;
(4x cubed)&lt;br /&gt;
(!x cubed)&lt;br /&gt;
(!4x to the fourth power)&lt;br /&gt;
(!3x squared)&lt;br /&gt;
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{{E}}&lt;br /&gt;
&amp;lt;br&amp;gt;&lt;br /&gt;
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{{MC}}&lt;br /&gt;
&lt;br /&gt;
&amp;#039;&amp;#039;&amp;#039;What is the derivative of a constant function?&amp;#039;&amp;#039;&amp;#039;&lt;br /&gt;
(Zero)&lt;br /&gt;
(!One)&lt;br /&gt;
(!The constant itself)&lt;br /&gt;
(!Undefined everywhere)&lt;br /&gt;
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{{E}}&lt;br /&gt;
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{{MC}}&lt;br /&gt;
&lt;br /&gt;
&amp;#039;&amp;#039;&amp;#039;Which statement describes the product rule?&amp;#039;&amp;#039;&amp;#039;&lt;br /&gt;
(Differentiate each factor once and add the two products)&lt;br /&gt;
(!Differentiate both factors and multiply the results)&lt;br /&gt;
(!Divide the first derivative by the second derivative)&lt;br /&gt;
(!Differentiate only the first factor)&lt;br /&gt;
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{{E}}&lt;br /&gt;
&amp;lt;br&amp;gt;&lt;br /&gt;
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{{MC}}&lt;br /&gt;
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&amp;#039;&amp;#039;&amp;#039;Which rule is designed for composite functions?&amp;#039;&amp;#039;&amp;#039;&lt;br /&gt;
(Chain rule)&lt;br /&gt;
(!Constant rule)&lt;br /&gt;
(!Secant rule)&lt;br /&gt;
(!Endpoint rule)&lt;br /&gt;
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{{E}}&lt;br /&gt;
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{{MC}}&lt;br /&gt;
&lt;br /&gt;
&amp;#039;&amp;#039;&amp;#039;What does a positive derivative usually indicate on an interval?&amp;#039;&amp;#039;&amp;#039;&lt;br /&gt;
(The function is increasing)&lt;br /&gt;
(!The function is constant)&lt;br /&gt;
(!The function is discontinuous)&lt;br /&gt;
(!The function is always negative)&lt;br /&gt;
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{{E}}&lt;br /&gt;
&amp;lt;br&amp;gt;&lt;br /&gt;
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{{MC}}&lt;br /&gt;
&lt;br /&gt;
&amp;#039;&amp;#039;&amp;#039;What is guaranteed if a function is differentiable at a point?&amp;#039;&amp;#039;&amp;#039;&lt;br /&gt;
(It is continuous at that point)&lt;br /&gt;
(!It has a maximum at that point)&lt;br /&gt;
(!Its derivative is zero there)&lt;br /&gt;
(!Its graph is a straight line)&lt;br /&gt;
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{{E}}&lt;br /&gt;
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{{MC}}&lt;br /&gt;
&lt;br /&gt;
&amp;#039;&amp;#039;&amp;#039;What does the second derivative of a position function represent?&amp;#039;&amp;#039;&amp;#039;&lt;br /&gt;
(Instantaneous acceleration)&lt;br /&gt;
(!Instantaneous position)&lt;br /&gt;
(!Average distance)&lt;br /&gt;
(!Constant speed)&lt;br /&gt;
&lt;br /&gt;
{{E}}&lt;br /&gt;
&amp;lt;br&amp;gt;&lt;br /&gt;
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{{MC}}&lt;br /&gt;
&lt;br /&gt;
&amp;#039;&amp;#039;&amp;#039;What is the slope of the tangent line to y equals f of x at x equals a?&amp;#039;&amp;#039;&amp;#039;&lt;br /&gt;
(The derivative at a)&lt;br /&gt;
(!The function value at zero)&lt;br /&gt;
(!The average of all function values)&lt;br /&gt;
(!The second derivative at every point)&lt;br /&gt;
&lt;br /&gt;
{{E}}&lt;br /&gt;
&amp;lt;br&amp;gt;&lt;br /&gt;
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{{BR}}&lt;br /&gt;
== Memory Game ==&lt;br /&gt;
&lt;br /&gt;
&amp;lt;div class=&amp;quot;memo-quiz&amp;quot;&amp;gt;&lt;br /&gt;
{|&lt;br /&gt;
|-&lt;br /&gt;
| Derivative || Instantaneous rate of change&lt;br /&gt;
|-&lt;br /&gt;
| Secant || Line through two points of a curve&lt;br /&gt;
|-&lt;br /&gt;
| Tangent || Local linear direction at a point&lt;br /&gt;
|-&lt;br /&gt;
| Limit || Value approached by a changing expression&lt;br /&gt;
|-&lt;br /&gt;
| Chain rule || Method for differentiating composite functions&lt;br /&gt;
|-&lt;br /&gt;
| Critical point || Candidate input for a local extremum&lt;br /&gt;
|}&lt;br /&gt;
{{E}}&lt;br /&gt;
&amp;lt;br&amp;gt;&lt;br /&gt;
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{{BR}}&lt;br /&gt;
== Drag and Drop ==&lt;br /&gt;
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&amp;lt;div class=&amp;quot;lueckentext-quiz&amp;quot;&amp;gt;&lt;br /&gt;
&lt;br /&gt;
{| class=&amp;quot;wikitable&amp;quot;&lt;br /&gt;
! Match the correct terms.&lt;br /&gt;
! Topic&lt;br /&gt;
|-&lt;br /&gt;
| &amp;#039;&amp;#039;&amp;#039;Difference quotient&amp;#039;&amp;#039;&amp;#039;&lt;br /&gt;
| Average rate of change over a shrinking interval&lt;br /&gt;
|-&lt;br /&gt;
| &amp;#039;&amp;#039;&amp;#039;Power rule&amp;#039;&amp;#039;&amp;#039;&lt;br /&gt;
| Efficient derivative rule for powers of x&lt;br /&gt;
|-&lt;br /&gt;
| &amp;#039;&amp;#039;&amp;#039;Product rule&amp;#039;&amp;#039;&amp;#039;&lt;br /&gt;
| Derivative method for a product of functions&lt;br /&gt;
|-&lt;br /&gt;
| &amp;#039;&amp;#039;&amp;#039;Chain rule&amp;#039;&amp;#039;&amp;#039;&lt;br /&gt;
| Derivative method for a composite function&lt;br /&gt;
|-&lt;br /&gt;
| &amp;#039;&amp;#039;&amp;#039;Second derivative&amp;#039;&amp;#039;&amp;#039;&lt;br /&gt;
| Rate of change of the first derivative&lt;br /&gt;
|}&lt;br /&gt;
{{E}}&lt;br /&gt;
&lt;br /&gt;
&amp;lt;br&amp;gt;&lt;br /&gt;
Match each mathematical idea to its role, then explain one match in your own words.&lt;br /&gt;
&amp;lt;br /&amp;gt;&lt;br /&gt;
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{{BR}}&lt;br /&gt;
== Crossword Puzzle ==&lt;br /&gt;
&lt;br /&gt;
&amp;lt;div class=&amp;quot;kreuzwort-quiz&amp;quot;&amp;gt;&lt;br /&gt;
{|&lt;br /&gt;
|-&lt;br /&gt;
| Derivative || What quantity gives an instantaneous rate of change?&lt;br /&gt;
|-&lt;br /&gt;
| Tangent || What line represents the local slope of a differentiable curve?&lt;br /&gt;
|-&lt;br /&gt;
| Secant || What line joins two points on a curve?&lt;br /&gt;
|-&lt;br /&gt;
| Limit || What concept describes a value approached by an expression?&lt;br /&gt;
|-&lt;br /&gt;
| Velocity || What derivative of position describes instantaneous motion?&lt;br /&gt;
|-&lt;br /&gt;
| Continuity || What property is guaranteed by differentiability at a point?&lt;br /&gt;
|}&lt;br /&gt;
{{E}}&lt;br /&gt;
&amp;lt;br&amp;gt;&lt;br /&gt;
&lt;br /&gt;
{{BR}}&lt;br /&gt;
== LearningApps ==&lt;br /&gt;
&lt;br /&gt;
&amp;lt;iframe&amp;gt; https://learningapps.org/index.php?s=Introduction+to+Differential+Calculus &amp;lt;/iframe&amp;gt;&lt;br /&gt;
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{{BR}}&lt;br /&gt;
== Cloze Text ==&lt;br /&gt;
&lt;br /&gt;
&amp;lt;quiz display=simple&amp;gt;&lt;br /&gt;
{&amp;#039;&amp;#039;&amp;#039;Complete the text.&amp;#039;&amp;#039;&amp;#039;&amp;lt;br&amp;gt;&lt;br /&gt;
|type=&amp;quot;{}&amp;quot;}&lt;br /&gt;
The central object in differential calculus is the { derivative }. A secant line measures an { average } rate of change between two points. Letting the second point approach the first uses a { limit }. The derivative at a point gives the slope of the { tangent } line. The derivative of a constant is { zero }. The rule for differentiating a product is the { product } rule. A composite function is differentiated with the { chain } rule. A positive first derivative usually indicates that a function is { increasing }. The derivative of position with respect to time is { velocity }. Differentiability at a point guarantees { continuity } there.&lt;br /&gt;
&amp;lt;/quiz&amp;gt;&lt;br /&gt;
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&amp;lt;br&amp;gt;&lt;br /&gt;
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{{BR}}&lt;br /&gt;
= Open-Ended Tasks =&lt;br /&gt;
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{{BR}}&lt;br /&gt;
=== Easy ===&lt;br /&gt;
# [[English:Slope Hunt|Slope Hunt]]: Find three examples of changing quantities in daily life, identify the input and output variables, and explain what an instantaneous rate of change would mean in each case.&lt;br /&gt;
# [[English:Derivative Sketchbook|Derivative Sketchbook]]: Draw a smooth function by hand, mark five points, estimate the tangent slope at each point, and sketch a possible derivative graph.&lt;br /&gt;
# [[English:Motion Interview|Motion Interview]]: Interview a classmate about how speed differs from average speed, then write a short explanation that connects the discussion to derivatives.&lt;br /&gt;
# [[English:Tangent Video|Tangent Video]]: Produce a one-minute video using a graph or physical demonstration to explain how a secant line can approach a tangent line.&lt;br /&gt;
&lt;br /&gt;
{{BR}}&lt;br /&gt;
=== Standard ===&lt;br /&gt;
# [[English:First Principles Investigation|First Principles Investigation]]: Use the limit definition to derive the derivative of a quadratic function of your choice and annotate every algebraic step.&lt;br /&gt;
# [[English:Optimization Poster|Optimization Poster]]: Design a poster that models and solves a realistic maximum-or-minimum problem, including assumptions, a derivative calculation, and an interpretation.&lt;br /&gt;
# [[English:Data Rate Study|Data Rate Study]]: Collect a small time-based data set such as cooling water, walking distance, or plant height, estimate rates of change, and compare average rates with an estimated instantaneous rate.&lt;br /&gt;
# [[English:Rule Comparison|Rule Comparison]]: Create a worked-example guide showing when to use the power, product, quotient, and chain rules, with one original example for each rule.&lt;br /&gt;
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{{BR}}&lt;br /&gt;
=== Advanced ===&lt;br /&gt;
# [[English:Numerical Differentiation Experiment|Numerical Differentiation Experiment]]: Use a spreadsheet or short program to approximate a derivative with difference quotients for progressively smaller step sizes, then analyze accuracy and rounding effects.&lt;br /&gt;
# [[English:Modeling Project|Modeling Project]]: Build a differentiable model for a changing real-world quantity, justify your chosen function, compute and interpret its derivative, and discuss limitations of the model.&lt;br /&gt;
# [[English:Proof Workshop|Proof Workshop]]: Derive either the product rule or the derivative of a simple power from the limit definition, then present the reasoning to peers and respond to questions.&lt;br /&gt;
# [[English:Calculus Teaching Video|Calculus Teaching Video]]: Produce a five-minute teaching video that connects limits, derivative notation, a differentiation rule, and one application while anticipating at least two common misconceptions.&lt;br /&gt;
&lt;br /&gt;
{{:Open Task - Create a MOOC}}&lt;br /&gt;
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{{BR}}&lt;br /&gt;
= Learning Assessment =&lt;br /&gt;
&lt;br /&gt;
# [[English:Conceptual Derivative Analysis|Conceptual Derivative Analysis]]: Given a graph of a function, explain where the derivative is positive, negative, zero, or undefined and justify each claim from the graph&amp;#039;s local behavior.&lt;br /&gt;
# [[English:First Principles Transfer|First Principles Transfer]]: Derive the derivative of a new simple function from the limit definition and compare the result with the appropriate differentiation rule.&lt;br /&gt;
# [[English:Motion Reasoning|Motion Reasoning]]: Analyze a position function to determine intervals of forward and backward motion, rest times, and acceleration, then interpret every result in context.&lt;br /&gt;
# [[English:Optimization Decision|Optimization Decision]]: Build and solve an optimization model from a written scenario, justify the domain, identify all candidates, and explain why the selected solution is optimal.&lt;br /&gt;
# [[English:Derivative Graph Reconstruction|Derivative Graph Reconstruction]]: Given information about the sign and zeros of a derivative, sketch a plausible original function and explain which features are forced and which are optional.&lt;br /&gt;
# [[English:Model Critique|Model Critique]]: Evaluate a real-world derivative claim, check units and assumptions, identify possible limitations, and propose evidence that would strengthen the conclusion.&lt;br /&gt;
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{{BR}}&lt;br /&gt;
= Evidence of Learning =&lt;br /&gt;
&lt;br /&gt;
# &amp;#039;&amp;#039;&amp;#039;Knowledge&amp;#039;&amp;#039;&amp;#039;: You can explain the derivative as a limit, tangent slope, instantaneous rate of change, and derivative function.&lt;br /&gt;
# &amp;#039;&amp;#039;&amp;#039;Skills&amp;#039;&amp;#039;&amp;#039;: You can differentiate basic and composite functions using first principles and standard rules, and you can interpret first and second derivatives.&lt;br /&gt;
# &amp;#039;&amp;#039;&amp;#039;Reasoning&amp;#039;&amp;#039;&amp;#039;: You can connect algebraic, graphical, numerical, and contextual representations and justify conclusions about increasing, decreasing, extrema, and concavity.&lt;br /&gt;
# &amp;#039;&amp;#039;&amp;#039;Products&amp;#039;&amp;#039;&amp;#039;: You can produce worked solutions, graphs, a data investigation, an optimization model, and an explanatory media product using correct mathematical language.&lt;br /&gt;
# &amp;#039;&amp;#039;&amp;#039;Transfer&amp;#039;&amp;#039;&amp;#039;: You can apply derivatives to unfamiliar problems in motion, science, economics, engineering, or other changing systems while checking units, assumptions, and reasonableness.&lt;br /&gt;
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{{BR}}&lt;br /&gt;
= OERs on the Topic =&lt;br /&gt;
&lt;br /&gt;
&amp;lt;iframe&amp;gt; https://en.m.wikipedia.org/wiki/Differential_calculus &amp;lt;/iframe&amp;gt;&lt;br /&gt;
&lt;br /&gt;
For further open study, you can also use [https://openstax.org/books/calculus-volume-1/pages/3-1-defining-the-derivative OpenStax Calculus Volume 1: Defining the Derivative] and related sections on derivative functions and differentiation rules.&lt;br /&gt;
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&amp;lt;br&amp;gt;&lt;br /&gt;
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{{BR}}&lt;br /&gt;
= Linked Learning Areas =&lt;br /&gt;
&lt;br /&gt;
{| align=center&lt;br /&gt;
{{:D-Tab}}&lt;br /&gt;
&amp;#039;&amp;#039;&amp;#039;[[English:Introduction to Differential Calculus|Introduction to Differential Calculus]]&amp;#039;&amp;#039;&amp;#039;&lt;br /&gt;
# [[English:Functions|Functions]]&lt;br /&gt;
# [[English:Limits|Limits]]&lt;br /&gt;
# [[English:Derivative|Derivative]]&lt;br /&gt;
# [[English:Differentiability|Differentiability]]&lt;br /&gt;
# [[English:Differentiation rules|Differentiation rules]]&lt;br /&gt;
# [[English:Chain rule|Chain rule]]&lt;br /&gt;
# [[English:Tangent|Tangent]]&lt;br /&gt;
# [[English:Rate of change|Rate of change]]&lt;br /&gt;
# [[English:Optimization|Optimization]]&lt;br /&gt;
# [[English:Kinematics|Kinematics]]&lt;br /&gt;
|}&lt;br /&gt;
&lt;br /&gt;
{{BR}}&lt;br /&gt;
= aiMOOC Projects =&lt;br /&gt;
[[Category:English]]&lt;br /&gt;
[[Category:Introduction to Differential Calculus]]&lt;br /&gt;
[[Category:Mathematics]]&lt;br /&gt;
[[Category:Calculus]]&lt;br /&gt;
[[Category:Differential calculus]]&lt;br /&gt;
[[Category:Grades 11-13]]&lt;br /&gt;
[[Category:Secondary education]]&lt;br /&gt;
[[Category:Physics]]&lt;br /&gt;
[[Category:AI_MOOC]]&lt;br /&gt;
[[Category:GPT aiMOOC]]&lt;br /&gt;
{{MT}}&lt;/div&gt;</summary>
		<author><name>Glanz</name></author>
	</entry>
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