posted by Jessica Maths
Multiply; then use fundamental identities to simplify the expression below and determine which of the following is not equivalent.
(sin x + cos x) ^2
c.sec x + 2 sin x/sec x
e. 1+2cos (pi / 2 - x) cos x
you know that sin^2 x + cos^2 x = 1, so when you expand you have
sin^2 x + 2 sinx cosx + cos^2 x
recall also that sec^2 x = 1 + tan^2 x
cos(pi/2-x) = sin(x)
So, what do you think?