Questions: Sketch the region of integration for the following integral.
[
int0^pi / 4 int0^5 / cos (theta) f(r, theta) r d r d theta
]
The region of integration is bounded by
A. y=0, y=x, and x=5
B. y=0, y=x, and y=5
C. y=0, x=sqrt25-y^2, and y=5
D. y=0, y=sqrt25-x^2, and x=5
E. None of the above
Transcript text: Sketch the region of integration for the following integral.
\[
\int_{0}^{\pi / 4} \int_{0}^{5 / \cos (\theta)} f(r, \theta) r d r d \theta
\]
The region of integration is bounded by
A. $y=0, y=x$, and $x=5$
B. $y=0, y=x$, and $y=5$
C. $y=0, x=\sqrt{25-y^{2}}$, and $y=5$
D. $y=0, y=\sqrt{25-x^{2}}$, and $x=5$
E. None of the above
Solution
Solution Steps
Step 1: Identify the region of integration
The given integral is:
\[
\int_{0}^{\pi / 4} \int_{0}^{5 / \cos (\theta)} f(r, \theta) r \, dr \, d\theta
\]
The limits of integration for \( r \) are from \( 0 \) to \( \frac{5}{\cos(\theta)} \), which describes a line \( x = 5 \) in Cartesian coordinates. The limits for \( \theta \) are from \( 0 \) to \( \frac{\pi}{4} \), which corresponds to the line \( y = x \).
Step 2: Determine the correct boundary description
The region of integration is bounded by:
\( y = 0 \) (the x-axis),
\( y = x \) (the line at \( \theta = \frac{\pi}{4} \)),
\( x = 5 \) (the line described by \( r = \frac{5}{\cos(\theta)} \)).
Thus, the correct answer is option A: \( y=0, y=x \), and \( x=5 \).
Final Answer
The region of integration is bounded by \( y=0, y=x \), and \( x=5 \).