Posted by archi on .
Find the volume of the solid obtained by rotating the region bounded by the given curves about the specified axis.
y=2+1/x^4,y=2,x=4,x=9;
about the xaxis.

calculus  please help! 
Steve,
Int(2 + 1/x^4  2 dx)[4,9]
= 1/3 x^3 [4,9]
= 1/3(1/729  1/64)
= 665/139968
= 0.00475 
calculus  oops 
Steve,
Sorry  we wanted a solid
v = Int(pi (R^2r^2) dx)
where R = y = 2+x^4
and r = 2
pi*Int(2+x^4)^2  4 dx [4,9]
pi*Int(4+4x^4 + x^8  4 dx)[4,9]
pi*Int(4x^4 + x^8 dx) [4,9]
pi*(28/x^3 + 1/7x^7)
= 0.0597 
calculus  please help! 
archi,
thank you soo much! :D

calculus  please help! 
Steve,
Hmm. I didn't see where you specified an axis. I rotated around the xaxis.