Question

Which equation is not an identity?

tan(–t) = –tan t



tan t(csc t + cot t) = sec t + 1



sin tcot t = cos t



cos2t − sin2t = –1

Answer 1

Not 100% positive but i believe it is the third choice

Answer 2

Hey there,

Let t = 0 and you'd get 1 - 0 = -1 which is false

I would go for (D)