List the steps IN ORDER to prove that: (sinx)(cosx)(tanx) + cos2x = 1 ?

1 Answer
Apr 14, 2018

Please see below.

Explanation:

.

#sinxcosxtanx+cos(2x)=1#

We have the following identities:

#tanx=sinx/cosx# and

#cos(2x)=1-2sin^2x#

Let's plug them in:

#sinxcosxsinx/cosx+1-2sin^2x=#

#sin^2x+1-2sin^2x=1-sin^2x=cos^2x#

The equation is not correct. If we had:

#2sinxcosxtanx+cos(2x)=1#

Then we could say:

#2sinxcosxsinx/cosx+1-2sin^2x=2sin^2x+1-2sin^2x=1#

Please check to make sure you posted the problem correctly.