MathDB
Period of Trigonometric Function

Source: 2017 AMC 12B #7

February 16, 2017
AMCAMC 12AMC 12 Bfunction2017 AMC 12B

Problem Statement

The functions sin(x)\sin(x) and cos(x)\cos(x) are periodic with least period 2π2\pi. What is the least period of the function cos(sin(x))\cos(\sin(x))?
<spanclass=latexbold>(A)</span> π2<spanclass=latexbold>(B)</span> π<spanclass=latexbold>(C)</span> 2π<spanclass=latexbold>(D)</span> 4π<spanclass=latexbold>(E)</span><span class='latex-bold'>(A)</span>\ \frac{\pi}{2}\qquad<span class='latex-bold'>(B)</span>\ \pi\qquad<span class='latex-bold'>(C)</span>\ 2\pi\qquad<span class='latex-bold'>(D)</span>\ 4\pi\qquad<span class='latex-bold'>(E)</span> It's not periodic.