AP Calculus AB

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

Advanced Topics

Definite Integrals and the Fundamental Theorem

From Area to Antiderivatives

The Fundamental Theorem of Calculus links differentiation and integration—it’s the bridge that connects the two main ideas of calculus.

The Fundamental Theorem

If \( F \) is an antiderivative of \( f \), then:

\[ \int_{a}^{b} f(x) , dx = F(b) - F(a) \]

This means you can compute definite integrals using antiderivatives!

How to Use It

  1. Find an antiderivative \( F(x) \) of \( f(x) \).
  2. Evaluate \( F \) at the upper and lower limits.
  3. Subtract: \( F(b) - F(a) \).

Why Is This Amazing?

You can calculate areas, solve accumulation problems, and connect the ideas of rates and totals—all with one powerful theorem.

Key Formula

\[\int_{a}^{b} f(x) , dx = F(b) - F(a)\]

Examples

  • Find the area under \( f(x) = 2x \) from \( x = 1 \) to \( x = 4 \) using the Fundamental Theorem.

  • Calculate the total distance traveled using the velocity function over a time interval.

In a Nutshell

The Fundamental Theorem connects derivatives and integrals, making calculating areas and totals much easier.

Key Terms

Fundamental Theorem of Calculus
A theorem that links derivatives and integrals, allowing us to evaluate definite integrals using antiderivatives.
Antiderivative
A function whose derivative is the original function.