Problem
Simplify and write the trigonometric expression in terms of sine and cosine: \[ \frac{1+\cos y}{1+\sec y}= \]
Solution
Step 1 ：Rewrite the secant function in terms of cosine: \(\frac{1 + \cos y}{1 + \frac{1}{\cos y}}\)
Step 2 ：Simplify the expression: \(\boxed{\cos y}\)
