Question

cosx/12=-1/2 найти х

Answer 1

$\cos\left(\frac{x}{12}\right)=-\frac12\\ x-?\\ \frac{x}{12}=\pm\arccos\left(-\frac12\right)+2\pi n=\pm\frac{2\pi}{3}+2\pi n\\ x=\pm8\pi+24\pi n$