### Home > CALC > Chapter 4 > Lesson 4.3.1 > Problem4-98

4-98.

To make this problem quicker to solve, remember that
y = cosx is an even function.

$=2\int_{0}^{\pi}\text{cos}xdx=2\left ( \text{sin}x\left|\begin{matrix} \pi \\ 0 \end{matrix}\right. \right )=2[\text{sin}\pi -\text{sin}0]=0$

Notice that this is an indefinite integral. Don't forget the +C.

2.7183 ≈ e (Euler's number) and the derivative of ln(x) is x−1.

Think! Trig identity. Simplify the integrand before you integrate.