Question

The expression cosx (cosx - tanx sinx) simplifies to _____?

Answer 1

Convert the tanx to (sinx)/(cosx), then distribute the cosx and simplify.

Answer 2

@DebbieG cos(2x)?

Answer 3

yup

Answer 4

No! How did you get that??

Answer 5

oops, sorry

Answer 6

the asker and me are correct, hehe

Answer 7

Oh, my bad... you are so right, lol..... I was doing it in my head, that'll teach me! ;) \[\cos x(\cos x-\frac{ \sin x }{\cos x }\sin x)=\cos^2x-\sin^2x=\cos(2x)\]