To find the area bounded by the curve x = f(y), the y-axis, and the lines y = c and y = d, the most direct integral to use is evaluated with respect to which variable?

To find the area bounded by the curve x = f(y), the y-axis, and the lines y = c and y = d, the most direct integral to use is evaluated with respect to which variable?

• A. y
• B. x
• C. Both x and y simultaneously
• D. Neither, it requires polar coordinates

Answer: A) y

Explanation: When boundaries are horizontal lines (y=c, y=d) and the curve is a function of y, integrating with respect to y is the direct method: ∫(c to d) f(y) dy.