AP Calculus AB

Advanced Placement Calculus AB covering limits, derivatives, and integrals.

Basic Concepts

Introduction to Derivatives

What Are Derivatives?

Derivatives measure how fast something changes—think of them as the mathematical version of speed! If you want to know how your position changes over time, the derivative gives you the velocity.

The Formal Definition

The derivative of a function \( f(x) \) at a point \( x \) is defined as:

\[ f'(x) = \lim_{h \to 0} \frac{f(x+h) - f(x)}{h} \]

How Do We Find Derivatives?

  • Power Rule: \( \frac{d}{dx} x^n = nx^{n-1} \)
  • Product Rule: \( (fg)' = f'g + fg' \)
  • Quotient Rule: \( \left(\frac{f}{g}\right)' = \frac{f'g - fg'}{g^2} \)
  • Chain Rule: Used for composite functions.

What Do Derivatives Tell Us?

  • Slope of the tangent line at a point
  • Instantaneous rate of change

Why Should You Care?

Derivatives help us model motion, growth, and lots of real-world phenomena!

Examples

  • If \( f(x) = x^2 \), then \( f'(x) = 2x \).

  • The slope of the curve \( y = \sin(x) \) at any point is \( \cos(x) \).

In a Nutshell

Derivatives show how a function is changing at any point.

Key Terms

Derivative
A measure of how a function's output changes as its input changes.
Tangent Line
A straight line that touches a curve at a single point and has the same slope as the curve at that point.