Concept:
The range of the sine and cosine functions is restricted to the interval \( [-1, 1] \). For the sum of two such functions to reach their combined maximum possible value (in this case, 2), each individual function must simultaneously equal its own maximum value of 1.
Step 1: Determine the values of \( x \) and \( y \).
Given \( \sin x + \cos y = 2 \), and knowing that \( \sin x \leq 1 \) and \( \cos y \leq 1 \), the only possibility is:
\[ \sin x = 1 \quad \text{and} \quad \cos y = 1 \]
Within the restricted interval \( [0, \frac{\pi}{2}] \):
• \( \sin x = 1 \implies x = \frac{\pi}{2} \)
• \( \cos y = 1 \implies y = 0 \)
Step 2: Calculate the sum \( x + y \).
\[ x + y = \frac{\pi}{2} + 0 = \frac{\pi}{2} \]