Question

Simplify the expression. (cos x)(sec x) - (sin^2 x)

cos x
cos2x
sec2x

Answer 1

The answer should be cos2x

Answer 2

`\cos^2x`

Explanation:

The given expression is:

`(\cos x)(\sec x)-\sin^2 x`

Recall form Pythagorean Identity that;

`\sec x=(1)/(\cos x)`

We apply this property to obtain;

`(\cos x)((1)/(\cos x))-\sin^2 x`

We simplify to get;

`1-\sin^2 x`

Recall from the Pythagorean identity that;

`1-\sin^2 x=\cos^2x`