Question

Which of the following is NOT an identity?
A. tan^2(x) = sec^2(x)-sin^2(x)-cos^2(x)
B. 1+(cos^2(x))/(sin^2(x)) = 1
C. (tanx + cotx)^2 = csc^2(x) + sec^2(x)
D. (cosx + sinx)^2 = 1 + 2cos(x) + sin(x)

Answer 1

I got it, it's B.