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This AP Calculus AB formula sheet covers the core tools students use to analyze change, motion, area, and accumulation. It brings together limits, continuity, derivative rules, graph interpretation, integrals, and major theorems in one organized reference. Students need this cheat sheet to review formulas quickly and connect procedures to AP-style reasoning.

It is especially useful when preparing for free-response questions that require both computation and explanation.

The main ideas are built around limits, rates of change, and accumulated change. Limits support continuity, derivatives describe instantaneous rates and slopes, and integrals measure net accumulation or signed area. The Fundamental Theorem of Calculus connects derivatives and integrals through functions such as F(x)=axf(t)dtF(x)=\int_a^x f(t)\,dt.

Many AP Calculus AB problems combine formulas with interpretation, units, and justification.

Key Facts

  • The limit definition of the derivative is f(x)=limh0f(x+h)f(x)hf'(x)=\lim_{h\to 0}\frac{f(x+h)-f(x)}{h}.
  • A function ff is continuous at x=ax=a when limxaf(x)=f(a)\lim_{x\to a}f(x)=f(a) and both sides of the equality exist.
  • The power rule is ddx(xn)=nxn1\frac{d}{dx}\left(x^n\right)=nx^{n-1} for real values of nn where the derivative is defined.
  • The product rule is ddx(uv)=uv+uv\frac{d}{dx}\left(uv\right)=u'v+uv' and the quotient rule is ddx(uv)=uvuvv2\frac{d}{dx}\left(\frac{u}{v}\right)=\frac{u'v-uv'}{v^2}.
  • The chain rule is ddx[f(g(x))]=f(g(x))g(x)\frac{d}{dx}\left[f(g(x))\right]=f'(g(x))g'(x).
  • A definite integral gives net accumulation, so abf(x)dx\int_a^b f(x)\,dx represents signed area or total change when ff is a rate.
  • The Fundamental Theorem of Calculus states that if F(x)=f(x)F'(x)=f(x), then abf(x)dx=F(b)F(a)\int_a^b f(x)\,dx=F(b)-F(a).
  • If A(x)=axf(t)dtA(x)=\int_a^x f(t)\,dt, then A(x)=f(x)A'(x)=f(x) wherever ff is continuous.

Vocabulary

Limit
A limit describes the value a function approaches as the input approaches a specified number.
Continuity
Continuity at x=ax=a means the function value exists, the limit exists, and limxaf(x)=f(a)\lim_{x\to a}f(x)=f(a).
Derivative
A derivative measures the instantaneous rate of change of a function and the slope of its tangent line.
Critical Point
A critical point occurs where f(x)=0f'(x)=0 or where f(x)f'(x) is undefined, provided f(x)f(x) is defined.
Definite Integral
A definite integral abf(x)dx\int_a^b f(x)\,dx measures signed area or net accumulated change over [a,b][a,b].
Fundamental Theorem of Calculus
The Fundamental Theorem of Calculus connects differentiation and integration by stating that accumulation functions have derivatives related to their integrands.

Common Mistakes to Avoid

  • Forgetting the chain rule, such as differentiating sin(3x)\sin(3x) as cos(3x)\cos(3x), is wrong because the inner derivative must be included, giving 3cos(3x)3\cos(3x).
  • Treating abf(x)dx\int_a^b f(x)\,dx as total area is wrong when f(x)f(x) is below the xx-axis because the definite integral gives signed area.
  • Using a derivative test without checking intervals is wrong because the sign of f(x)f'(x) must be analyzed on both sides of a critical point to justify increasing, decreasing, or extrema.
  • Assuming a function is continuous because it is defined at x=ax=a is wrong because continuity also requires limxaf(x)=f(a)\lim_{x\to a}f(x)=f(a).
  • Dropping the constant in an indefinite integral, such as writing 2xdx=x2\int 2x\,dx=x^2, is incomplete because the full family of antiderivatives is x2+Cx^2+C.

Practice Questions

  1. 1 Find ddx(x3sinx)\frac{d}{dx}\left(x^3\sin x\right).
  2. 2 Evaluate 142xdx\int_1^4 2x\,dx.
  3. 3 If A(x)=2xt2+1dtA(x)=\int_2^x \sqrt{t^2+1}\,dt, find A(3)A'(3).
  4. 4 Explain how the sign of f(x)f'(x) and the sign of f(x)f''(x) describe the shape and behavior of the graph of ff.

Understanding AP Calculus AB Formula Sheet

A formula sheet is most useful when you first decide what kind of information a problem gives. A table of values may call for an average rate of change or a numerical approximation. A graph may require reading slopes, signs, turning points, or accumulated area.

An equation may require a derivative rule or an antiderivative. Before choosing a rule, identify the output the question asks for. A value of a derivative has units of output per input.

If distance is measured in meters and time in seconds, velocity is measured in meters per second. Units often reveal whether an answer makes sense.

Limits describe what happens near an input, not necessarily at that input. This distinction matters for holes, jumps, vertical asymptotes, and piecewise functions. A limit can exist even when the function has no value at the point.

A function can have a value that does not match its nearby behavior. For continuity, the left side, right side, and actual function value must agree. On AP problems, students should state the exact reason a function is not continuous.

A jump means the one-sided limits differ. A removable discontinuity means the nearby values approach one number but the function value is missing or different. An infinite limit is not a finite real number.

Derivatives are more than rules for simplifying expressions. They describe how a quantity changes at one moment. For a position function, the first derivative gives velocity and the second derivative gives acceleration.

A positive velocity means position is increasing. A negative velocity means position is decreasing. The sign of acceleration describes how velocity changes, not whether an object moves left or right.

An object speeds up when velocity and acceleration have the same sign. It slows down when their signs differ.

On a graph of a function, a horizontal tangent can signal a critical point, but it does not guarantee a maximum or minimum. Check how the derivative changes sign on either side.

Integrals require careful interpretation because they track net change. Values above the horizontal axis contribute positively. Values below contribute negatively.

Therefore, a definite integral may be zero even when there is substantial geometric area on both sides of the axis. If a problem asks for total distance, separate intervals where velocity is positive or negative, then add the positive distances. When a rate is given, integration restores the accumulated quantity.

A flow rate in liters per minute produces a change in liters. The Fundamental Theorem explains why this works and provides an efficient method when an antiderivative is available. For an accumulation function, its derivative equals the original rate at the current input.

Students should distinguish the accumulation value from its derivative. One measures total change since a starting point. The other measures the current rate of change.