# Pleaaaase help me

1. Dec 2, 2004

### Habosh

hi
this is my first post,and I hope i get the help I need;)
equation of curve 2y^2=x^3 find the volume of the solid formed by the complete rotation about the y axis of the region bounded by the curve the y azis and the line with the equation y=2 which lies in the first quadrant,*done this*
npw i need help in second part of the question
find also the volume formed when the region is rotated completely about the x axis
I also have a question would anyone help me and explain what shall we do if the rotation was not 360 about the x axis,but was 180

2. Dec 2, 2004

### Tide

Rotating about the x axis is mathematically equivalent to swapping x and y in the relation given then rotating about the y axis so that whatever method you used in the first problem should work for the second problem.

Also, rotating halfway will give you half the volume of a full rotation.

3. Dec 2, 2004

### Habosh

well that is what driving me crazy,because in the second one I tried to make the equation with the y as a subject then squared it and substituted with 2 but it didn't work the answer was wrong:(

4. Dec 2, 2004

### mathwonk

suggestion: curiosity is more powerful an attraction than academic pity. try stating the problem next time in the title. your current title has been used a lot before, and to me personally is often reason enough to ignore the post.

5. Dec 2, 2004

### Habosh

hehe:Dok then i will next time i'll post a thread with the title I have a phsycic powers is a math fourm:p that will surely attract some attention