Question

No idea how to solve. Find all solutions in the interval [0, 2π). cos x = sin x

Answer 1

$\cos x=\sin x\\ \tan x=1\\ x=\dfrac{\pi}{4}+k\pi,k\in \mathbb{Z}$

In the given interval, the solutions are $\dfrac{\pi}{4},\dfrac{5\pi}{4}$