Simplify. Sin^2?cos^2?-cos^2?

Question

I have to simplify that particular expression. But I thought that maybe the cos would cancel. I'm not sure what to do

Answer 1

sin² x cos² x - cos² x

 

= (sin² x - 1)cos² x

 

= -cos² x cos² x

 

= -cos⁴ x

Answer 2

The cosine terms would cancel out  With that hint, you should be able to figure out the answer.  Keep in mind that this is basic algebra, although you are working with trigonometry.