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**1. Find the volume for the solid obtained by rotating the region bounded by the given curves about the specified line. y=(1/4)(x^2), x = 2, y = 0, about the y axis**

**2. Use the disk/washer method of integration to find the volume**

**3. When I try to solve this problem using small changes in x (dx) I get the wrong answer. Method: Take integral from 0 to 2 of a function for the area of a circle.**

∫ from 0 to 2 : 2[(∏)*((x^2)/8)^2] dx → ∫ from 0 to 2 : (∏x^4)/32 → ∏/5

I do not see why I need to use the washer method as using the disk method encounters no hollow space

the answer given is 2pi

Please tell what I'm doing wrong.

Thanks

I'm not comfortable with the washer method, that's why I solved the problem with small change in the x axis.

∫ from 0 to 2 : 2[(∏)*((x^2)/8)^2] dx → ∫ from 0 to 2 : (∏x^4)/32 → ∏/5

I do not see why I need to use the washer method as using the disk method encounters no hollow space

the answer given is 2pi

Please tell what I'm doing wrong.

Thanks

I'm not comfortable with the washer method, that's why I solved the problem with small change in the x axis.