AP Calc AB Study Guide
- Credit: Simplestudies.org
- This study guide has a lot of images so if u cant scroll to the very bottom without jittering just let it load for a bit
- Here is a Cheat Sheet/Shorter and compressed version of what's described. Final Notes for AB and BC
- Limit evaluation chart: here
- Key words pdf here
Unit 1 – Limits and Continuity
What is a limit and how to find it:
Limit: If f(x) becomes close to a unique number L as x approaches c from either side, then
the limit of f(x) as x approaches c is L.
- A limit refers to the y-value of a function
* The general limit exists when the right and left limits are the same_equal each other
- DNE = does not exist.
Examples of estimating a limit numerically:
Example of using a graph to find a limit:
When limits don’t exist:
When the Left limit ≠ Right limit, then the limit is said to not exist.
- In the picture below, you can tell that the two limits don’t equal each other, thus theanswer to this limit is DNE.
Evaluating Limits Analytically:
Limits Theorem:
Given:
Lim and Lim
* If m<n, then the limit equals 0
- If m=n, then the limit equals a_b
- If m>n, then the limit DNE
Finding Vertical Asymptotes
The only step you have to do is
set the denominator equal to zero and solve.
-
- (x+2)(x-2) = 0 → x = 2, -2
- 2 is a removable hole while -2 is the non-removable vertical asymptote.
Finding Horizontal Asymptotes
Use the
two terms of the highest degree in the numerator and denominator
-
- x and x2 are the two terms of the highest degree in the numerator and denominatorrespectively. After finding it, use the limits at infinity rule to determine the limit.
Intermediate Value Theorem
A continuous function on a
closed interval cannot skip values.
● f(x) must be continuous on the given interval [a,b]
● f(a) and f(b) cannot equal each other.
● f© must be in between f(a) and f(b)
Example #1: Apply the IVT, if possible on [0,5] so that f©=1 for the function
f(x)=x2+x+1
- f(x) is continuous because it is a polynomial function.
- f(a)=f(0)=1f(b)=f(5)=29
- By the IVT, there exists a value c where f©=1 since 1 is between -1 and 29.Example #2:
Example #2:
- For 0<t<60, must there be a time t when v(t) = -5?
- f(a) = f(0) = -20f(b) = f(60) =10
- By the IVT, there is a time t where v(t)=-5 on the interval [0,60] since -20 < -5 < 10
The Squeeze Theorem
Unit 2 - Differentiation: Definition and Basic Derivative Rules
What is a derivative?
- Derivative: The slope of the tangent line at a particular point; also known as theinstantaneous rate of change.
- The derivative of f(x) is denoted as f’(x) or
Steps to find derivatives as limits:
- Identify the form of the derivative first (look at the image above)… is it form a? b? c?
- Identify f(x)
- Derive f(x) using the corresponding equations next to each form
- Plug in the “c” value if applicable
Rules of Differentiation
Derivatives of Trigonometric Functions:
* HINT: If the original function starts with C, then the derivative is negative!
- Example: cosx, cotx, & cscx
Derivative Rule for LN
- Example: h(x) = ln(2x^2 + 1)
- First derive 2x^2 + 1. That would be 4x! And then put that over theoriginal function, which would be 2x^2 + 1.
- Your answer would then be 4x_(2x^2 + 1)
Deriving Exponential Functions
Continuity
A function f is continuous at “c” if:
- The value exists- The value of the function is defined at “c” and f© exists
- The limit exists - The limit of the function must exist at “c”
- The left and right limits must equal
- Function=limit. The value of the function at “c” must equal the value of the limit at “c”
Discontinuity
- Removable → discontinuity at “c” is called removable if the function can becontinuous by defining f©
- Non-removable → discontinuity at “c” is called non-removable if the function cannotbe made continuous by redefining f©
Differentiability
In order for a function to be differentiable at x = c:
- The function must be continuous at x = c
- Its left and right derivative must equal each other at x = c
Example:
Unit 3 - Differentiation: Composite, Implicit, and InverseFunctions
The Chain Rule
The chain rule helps us find the derivative of a composite function. For the formula, g’(x)
would be the chain.
We use the general rule power when finding the derivative of a function that is raised to the
nth power
. In the formula given, f’(x) is the chain.
Implicit Differentiation
Inverse Trig Functions: Differentiation
Unit 4 - Contextual Applications of Differentiation
Particle Motion
- s(t) represents the position function, aka f(x)
- t stands for time, s(t) is the position at a specific time.
- v(t) represents the velocity function, aka f’(x)
- t stands for time, v(t) is the speed and direction at a specific time.
- Velocity is the derivative of position.
- A particle is moving to the right or up when velocity is positive.
- A particle is moving to the left or down when velocity is negative.
- A particle’s position is increasing when velocity is positive.
- A particle’s position is decreasing when its velocity is negative.
- A particle is at rest or stopped when its velocity is zero
- a(t) represents the acceleration function aka f’’(x)
- t stands for time, a(t) is the rate at which the velocity is changed at specific times
- Example: s(t)=6t^3 -4t^2 → v(t)=18t^2 -8t → a(t)=36t-8
Particle Moving Away_Toward the Origin(x-axis)
* A particle is moving towards the origin when its position and velocity have opposite signs.
- A particle is moving away from the origin when its position and velocity have the samesigns,
Particle Speeding Up_Slowing Down
* A particle is speeding up (speed is increasing) if the velocity and acceleration have thesame signs at the point
- A particle is slowing down (speed is decreasing) if the velocity and acceleration haveopposite signs at the point.
Related Rates
What is the purpose of related rates?
- The purpose is to find the rate where a quantity changes
- The rate of change is usually with respect to time
How to solve it?
- Identify all given quantities to be determined.
- Make a sketch of the situation and label everything in terms of variables, even if you aregiven actual values.
- Find an equation that ties your variables together.
- Using chain rule, implicitly differentiate both sides of the equation with respect to time.Substitute or plug in the given values and solve for the value that is being asked for
- *Don’t forget to put the correct units!
The Different Types of Related Rates Problems
- Algebraic
- Circle
- Triangles
- Cube
- Right Cylinder
- Sphere
- Circumference
Related Rates: Algebraic
Example: A point moves along the curve y = 2x^2 - 1 in which y decreases at the rate of 2 units
per second. What rate is x changing when x = -3_2?
Example: The radius of a circle is increasing at a rate of 3cm_sec. How fast is the circumference
of the circle changing?
Example: A 13ft ladder is leaning against a wall. If the top of the ladder slips down the wall at a
rate of 2 ft_s, how fast will the ladder be moving away from the wall when the top is 5ft above
the ground?
Example: The volume of a cube is increasing at a rate of 10cm^3_min. How fast is the surface area
increasing when the length of an edge is 30cm?
Example: The radius of a right circular cylinder increases at the rate of 0.1cm_min and the height
decreases at the rate of 0.2 cm_mm. What is the rate of change of the volume of the cylinder, in
cm3_min, when the radius is 2cm and the height is 3cm?
Example: As a balloon in the shape of a sphere is being blown up, the volume is increasing at a
rate of 4in3_s. At what rate is the radius increasing when the radius is 1 inch.
Example: What is the value of the circumference of a circle at the instant when the radius is
increasing at 1_6 the rate the area is increasing?
Let f and g be continuous and differentiable functions on an open interval (a,b). If the limit of
f(x) and g(x) as x approaches c produces the indeterminate form 0_0 or ∞_∞ then,
Unit 5 - Analytical Applications of Differentiation
Mean Value Theorem
If f(x) is a function that is continuous on the closed intervals [a,b] and differentiable on the
open interval (a,b),
then there must exist a value c between (a,b)
* Example: Confirm f(x)=x^3 on [0,3] and find a value that satisfies this theorem
Function Increasing or Decreasing
- f(x) is increasing when f’(x) is positive
- f(x) is decreasing when f’(x) is negative
Extreme Value Theorem
If f(x) is continuous on a closed interval [a,b], then f(x) has both a minimum and maximum on the interval.
(Absolute max on top and absolute min on bottom)
For first derivative tests, derive the function once and set it to 0. After that, find the zeros and
plug them into a number line. Using your derived function, plug-in numbers before and after
your constant (the zeros of the function) to see if it becomes negative or positive, as shown
below.
- If it’s positive, constant, negative then it’s a relative maximum
- If it’s negative, constant, positive then it’s a relative minimum
- The graph of f is concave up when f’(x) is increasing
- The graph of f is concave down when f’(x) is decreasing
- If f’’(x) is positive then the graph of f is concave up
- If f’’(x) is negative then the graph of f is concave down
- Occurs when f(x) changes concavity
- Determined by a sign change for f’’(x)
Second Derivative Test
Example:
- Critical numbers are points on the graph of a function where there’s a change in direction.
- To find critical numbers, you use the first derivative of the function and set it to zero.
Unit 6 - Integration and Accumulation of Change
Riemann Sums
You use Riemann sums to find the actual area underneath the graph of f(x).
The area under the curve of derivatives of F from A to B is equal to the change in y-values of the
function F from A to B, given f is:
- Continuous in interval [a,b]
- F is any function that satisfies F(x)=f’(x)
What is an indefinite integration?
Given y' or f '(x), the anti-derivative can be thought of as the
original function, f(x). Integration
is
used to find the original function.
- The operation of finding all solutions to this equation is called antidifferentiation or
indefinite integration
.
- Detonated by an integral sign: ∫
- dx = variable of integration
- f(x) = antiderivative
- c = constant of integration
- ∫ = integral
Reminder: ALWAYS add +C when you’re solving for an INDEFINITE integral!
Reminder: Differentiation and integration are inverses!
Basic Integration Rules (w_ examples)
C is still a constant when multiplied by 2 (a constant multiplied by a constant is still a constant)
- HINT: How I memorize antiderivatives by using derivatives of trigonometric functions
- EX: d_dx sinx = cosx and for the antiderivative, you just switch the twotrigonometric functions and add +C since it’s an indefinite integration.
- EX: d_dx cscx = -cscxcotx and for the antiderivative, just switch the twotrigonometric functions and add +c since it’s an indefinite integration. Also, if thederivative was negative, then the anti-derivative is also negative!
Integration by U-substitution
Natural Log Function for Integration (Log rule for integration)
Use this rule when ‘x’ becomes DNE
Integrals of the 6 Basic Trig Functions
* HINT: For ∫ tan u du, I memorized it like this: ∫ tan u du = ∫ sin u_cos u du because of the trigonometric identities. After that, I just did u-substitution with cos u being u.
- If you work it out, it looks like this:
● With e, it’s just the same thing as regular u-substitution but with the additional ‘e’.
Unit 7 - Differential Equations
Differential Equations (Separate the integral)
Differential Equation with Initial condition
A visual depiction of a differential equation of dy_dx.
- Example of what a slope field looks like
Unit 8 – Applications of Integration
Average Value
- To find the average value, integrate the function by using the fundamental theorem of
calculus
- After that, divide the answer by the length of the interval
- The difference between the starting position and ending position
- Interval [a,b]
- Can be negative
- Formula:
- Total distance traveled by a particle is the sum of the amounts it displaces betweenthe start, all of the stop(s), and the end.
- Distance can’t be negative
- Formula:
Area of a Region Between Two Curves
If a region in the plane revolves about a line, the resulting solid is a solid of revolution, and
the line is called the
axis of revolution. The simplest solid is a right circular cylinder or disk,
which is formed by revolving a rectangle about an axis adjacent to one side of the rectangle.
- Rotate Around x-axis
- The horizontal axis of revolution
- Rotate Around y-axis
- The vertical axis of revolution
The Washer Method
- Horizontal Line of Rotation:
The Washer Method Calculating Volume Using Integration
Step One: Draw a picture of your graph→ shade appropriate region
Step Two: Identify whether you are rotating about a vertical or horizontal line
- Vertical
- Get everything in terms of y
- Horizontal
- Get everything in terms of x
Step Three: Set up your Integral