Machine-translated by Google. Questions are authored in English.
Top

Discussion

The volume of the cylinder \( x^{2} + y^{2} \le 4 \) between \( z = 0 \) and \( z = 5 \) by triple integration is

  • A.\( 20\pi \)
  • B.\( 40\pi \)
  • C.\( 10\pi \)
  • D.\( 80\pi \)

Answer: A

In cylindrical coordinates the three integrals separate:

\[ V \;=\; \int_{0}^{2\pi}\!\!\int_{0}^{2}\!\!\int_{0}^{5} r\,dz\,dr\,d\theta \;=\; (2\pi)\left(\frac{4}{2}\right)(5) \;=\; 20\pi. \]

This is \( \pi r^{2}h = \pi(4)(5) \). Using the radius rather than its square would double the answer to \( 40\pi \)

No comment is present. Be the first to comment.
Loading…

Post your comment

Please log in or register to post a comment.