find the volume of the curves rotated about the x-axis

**racewithferrari** · July 11th 2010, 09:25 AM

the endpoint comes -1 and 1

and I am taking the integral of ((9/8)-x^2)-(x^2/8)....and then multiplyig by 2pi.

the final answers come 3pi.

Any help

thanks

**skeeter** · July 11th 2010, 09:59 AM

method of washers ...

$\displaystyle V = \pi \int_a^b [R(x)]^2 - [r(x)]^2 \, dx$

**racewithferrari** · July 11th 2010, 11:28 AM

Originally Posted by skeeter

method of washers ...

$\displaystyle V = \pi \int_a^b [R(x)]^2 - [r(x)]^2 \, dx$

so its like this

with end points of -1 and 1

**skeeter** · July 11th 2010, 11:46 AM

Originally Posted by racewithferrari

so its like this

with end points of -1 and 1

second term in the integrand should be $\left(\frac{x^2}{8}\right)^2$ if what you posted originally is correct ...

$\frac{x^2}{8} \ne \frac{1}{8x^2}$

also ... limits of integration?

Thread: find the volume of the curves rotated about the x-axis

LinkBack

Thread Tools

Display

find the volume of the curves rotated about the x-axis

Similar Math Help Forum Discussions

Parametric Curves and Volume of the area rotated about y-axis

Volume of a solid rotated aroun the x axis

volume of a solid rotated about the y-axis

Volume for region rotated around the x-axis

Volume of a curve rotated around the y-axis

Search Tags