Using polar coordinates to find the volume of the given solid

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To find the volume of the solid inside the sphere defined by x^2 + y^2 + z^2 = 16 and outside the cylinder x^2 + y^2 = 4, polar coordinates are utilized. The correct approach involves setting up a double integral with limits for theta from 0 to 2π and for r from 2 to 4. The integrand is formulated as ((16 - r^2)^(1/2))r (dr)(dtheta). The discussion confirms that the integral's setup is accurate, focusing on the volume outside the cylinder. This method effectively calculates the desired volume of the solid.
serg_yegi
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1. Use polar coordinates to find the volume of the given solid.
2. Inside the sphere x^2 + y^2 + z^2 = 16 and outside the cylinder x^2 + y^2 = 4.
 
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serg_yegi said:
1. Use polar coordinates to find the volume of the given solid.



2. Inside the sphere x^2 + y^2 + z^2 = 16 and outside the cylinder x^2 + y^2 = 4.
What have you tried? You have to show an effort first.
 
I've tried doing a double integral from theta=0 to theta=2pi and r=0 to r=4 of ((16-r^2)^(1/2))r (dr)(dtheta)
 
The limits of integration for r should be from r = 2 to r = 4. If you go from r = 0, you're getting the volume inside the cylinder, which you don't want.
 
Ok. Is the actual integral correct?
 
Yes, I don't see anything wrong with it.
 
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

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