Answer
$$\frac{1-\sin^2\beta}{\cos\beta}=\cos\beta$$
We simplify the left side, using Pythagorean Identity for the numerator.
Work Step by Step
$$\frac{1-\sin^2\beta}{\cos\beta}=\cos\beta$$
The left side is more complex, so we would simplify it first.
$$A=\frac{1-\sin^2\beta}{\cos\beta}$$
According to a Pythagorean Identity,
$$1-\sin^2\beta=\cos^2\beta$$
$A$ would become
$$A=\frac{\cos^2\beta}{\cos\beta}$$
$$A=\cos\beta$$
The left side has been simplified to the right side. It is thus an identity.