Question

find all real numbers that satisfy equation:
2cosx=-1

Answer 1

\(\bf 2cos(x)=-1 \implies cos(x)= -\cfrac{1}{2}\\
\textit{now, taking } cos^{-1}\\
cos^{-1}(cos(x)) = cos^{-1}\left(-\cfrac{1}{2}\right)\)

Answer 2

@jdoe0001
has solutions x|x=__2pik and x|x=__2pik

Answer 3

__+2pikfor each one actually

Answer 4

so get the arcCos of both sides