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C3 Integration by parts

∫x^2cosx dx

let u = x^2 so du/dx = 2x
let dv/dx= cosx so v = sinx

im up to x^2sinx - 2xsinx and don't know where to go from there..

Reply 1

B_9710

Original post by AndyOC

∫x^2cosx dx

let u = x^2 so du/dx = 2x
let dv/dx= cosx so v = sinx

im up to x^2sinx - 2xsinx and don't know where to go from there..

Integrate the 2xsinx by parts. This should then give you something which is very easy to integrate. When integrating by parts you often have to do it twice to get the answer.

Reply 2

AndyOC

Original post by B_9710

Integrate the 2xsinx by parts. This should then give you something which is very easy to integrate. When integrating by parts you often have to do it twice to get the answer.