Question

Which equation is NOT an identity?
*will fan and medal*
a) tan(-t)=-tan t

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

c) sin tcot t = cos t

d) cos^2t − sin^2t = –1

Answer 1

D

Answer 2

Cos^2t -sin^2 t=cos (2t)

Answer 3

Thanks so much!

Answer 4

Don't mention it