To simplify the expression, we can first recognize that sin^2a + cos^2a = 1, due to the Pythagorean identity for sine and cosine functions.

Therefore, the expression simplifies to:
1 + sin^2a/cos^2a

Now, we can rewrite sin^2a as (1 - cos^2a) using the Pythagorean identity again:
1 + (1 - cos^2a)/cos^2a
1 + (1/cos^2a) - 1
1/cos^2a

So, the simplified expression is 1/cos^2a or sec^2a.