Question

cos^x(sec^2x-1)
what pythagoream identiy to use?

Answer 1

first multiply them out.
like a(b-c) = ab-ac
so whats cos^x(sec^2x-1) = ... - ... ?

Answer 2

yeahhhhh right hartnn

Answer 3

cos^2x(sec^2x) - cos^2x-1

Answer 4

yup, and you know what cos x * sec x = .. ?

Answer 5

and -1 won't come.

Answer 6

\(\large \cos^2x(\sec^2x-1)=\cos^2x\sec^2x-\cos^2x = ...?\)

Answer 7

can u simplify that ^ ?
use the fact that cos x = 1/ sec x.

Answer 8

should i use factorization in this

Answer 9

nopes.
since, cos x = 1/ sec x
what is cos x * sec x = ... ?

Answer 10

should i turn secant into cos

Answer 11

yes., do that...what u get ?