Question

Cos(5pi-4x) =- корень 3/2

Answer 1

На фотографии подробно.

Answer 2

$cos\Big(5\pi-4x\Big)=-\frac{\big{\sqrt{3}}}{\big2}\\\\-cos4x=-\frac{\big{\sqrt{3}}}{\big2}\\\\cos4x=\frac{\big{\sqrt{3}}}{\big2}\\\\4x=\pm\:\frac{\big{\pi}}{\big6}+2\pi\:k\\\\\boxed{\:\:x\:_k=\pm\:\frac{\big{\pi}}{\big{24}}+\frac{\big{\pi\:k}}{\big{2}}\:\:,\:\:\:\:k\:\in\:\mathbb{Z}\:\:}$