Question

Integral :)

Answer 1

\[\int\limits (x-1)\sin(\Pi x)\]

Answer 2

Is that pi?

Answer 3

taht is Pi :)... so if I make dv=Sin(Pi*x), can I take out Pi? so v=-Picos(x)?

Answer 4

Basically. The derivative of sin(ax) = -a(cos(ax)), after all. And then you just do the rest of integration by parts.

Answer 5

oh cool :) I'll work on it and maybe you can help me by checking?

Answer 6

Sure, no problem.

Answer 7

@greenglasses like this?

Answer 8

I think I found a mistake on that ;/

Answer 9

Yeah, I'm not sure where you got the 2pi.

Answer 10

it should be (Pi)^2

Answer 11

I'm getting (x-1)(-pi cos(pi.x)) -sin(pi.x) + c

Answer 12

the v=-Pi(Cos[Pi*x])

Answer 13

Yeah, the integral of cos(pi.x) would be (1/pi)(sin(pi.x)), not pi(sin(pi.x)). The two pis would cancel out.

Answer 14

hmm I see... so then in your second comment, did you mean derivative or integral of Sin(ax)=-aCox(ax)?

Answer 15

I got confused lol

Answer 16

Second comment I meant derivative.

Answer 17

It's the opposite when you're going the other way 'round.