Question 84049
Realistically, we can conclude that there will be no negative values for when cos = -x .. cos = -x ~> -x * -x = +x^2
So whenever cos(x) = +- 1 ...
-2{{{pi}}} , -{{{pi}}} , {{{0}}} , {{{pi}}} , 2{{{pi}}}
{{{graph(600,150,-6.3,6.3,-1,1,cos(x)^2,1)}}}