## infinitemoes 2 years ago For a particular angle θ, the cosine function has the following values within one cycle of the function: cos 0=3, cos π/4=0, cos π/2=-3, cos 3 π/4 = 0, cos π=3 What is the rule of the cosine function?

general cosine equation: $y = Acos(Bx)$ from the unit circle we know that cos(0) = 1 A = 3 also we know that cos(pi) = -1 3 = 3cos(Bpi) 1 = cos(Bpi) thus B = 2 $y = 3\cos(2x)$