cos(180-x)=-cos x verify it with identities. @StudyGurl14 can you possibly help me out? i will give medal to best answer! thanks

Question

dumbcow · Answer

|dw:1416342078293:dw|

anonymous · Answer

it is a verification problem, identities need to be used to make one side identical to the other. the picture does not verify it.

dumbcow · Answer

ok but the picture does indeed show that they are equal using the unit circle

anyway you need to use this property for difference of angles
$$\cos(a-b) = \cos a \cos b + \sin a \sin b$$

anonymous · Answer

ohhhh thanks! i completely forgot about that identity!