## Calculus: Early Transcendentals 8th Edition

The formula for the arc length of a curve on the interval (a,b) is $_{a}\int^{b}(\sqrt {1+(dy/dx)^2}$. The derivative of the function $sin(x)$ with respect to x is $cos(x)$. Therefore, the answer is simply $_{0}\int^{\pi}(\sqrt {1+(cos(x))^2}$ which when plugged into a calculator yields 3.8201977890.