I know this is d u m b but I’m confused on how to describe the pattern

Which sum or difference identity would you use to verify that cos (180° - ∅) = -cos ∅? a. sin (α -β) = sin α cos β – cos α sin β b. cos (α -β) = cos α cos β – sin α sin β c. cos (α -β) = cos α cos β + sin α sin β d. sin (α + β) = sin α cos β + cos α sin β

Any is very appreciated! (picture is provided below)not sure how to do this at all won't lie

The functions f(x) and g(x) are shown in the graph f(x)=x^2 what is g(x) ?