Question

Simplifying sec× cos(-×)-sin^2 ×

Answer 1

`\sec x \cos(-x)-\sin^2x = \sec x \cos x - \sin^2x`, since cos is an even function. (This means cos(-x) = cos(x))


`=1-\sin^2x`, since
`\sec x \cos x = 1`


`= \cos^2x`, by
`\sin^2x+\cos^2x=1`.