Question

Let $f:[0,4 \pi] \rightarrow[0, \pi]$ be defined by $f(x)=\cos ^{-1}(\cos x)$. The number of points $x \in[0,4 \pi]$ satisfying the equation $f(x)=\frac{10-x}{10}$ is

Answer 1

SOLUTION : $f(x)=\left(\sin ^{-1}\right) x \in[0,4 \pi]$

\& $\quad f(x)=\frac{10-x}{10}=1-\frac{x}{10}$

so, 3 solution