Can you solve this for me please?

If #sin theta+sin^2 theta=1# then prove that #cos^2 theta+cos^4 theta=1#

1 Answer
Apr 4, 2018

Please see below.

Explanation:

Here,

#sintheta+sin^2theta=1#

#=>sintheta=color(red)(1-sin^2theta#

#=>color(blue)(sintheta)=color(red)(cos^2theta)....to(A)#

We know that,

#color(brown)(cos^2theta+sin^2theta=1#

#=>cos^2theta+color(blue)((sintheta)^2)=1#

#=>cos^2theta+color(red)((cos^2theta)^2)=1....to#,Using #(A)#

#=>cos^2theta+cos^4theta=1#