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View Full Version : x*ln(x) == 1/2x^2*ln(x) - 1/4*x^2 not sure how they got it


mr_coffee
Mar28-07, 04:24 PM
Hello everyone!

I'm doing a line integral but i'm confused on the integration method used:

I got to integral 1 to 3 2*(x^4+xln(x) ); But they then have:
x^5/5 + 1/2x^2 * ln(x) - 1/4x^2 and i'm not sure how they got the last part, 1/2x^2 * ln(x) - 1/4x^2

Thanks!

u = x isn't what they did I don't think, and its been awhile so i'm rusty on integration XD

Dick
Mar28-07, 04:29 PM
The 'hard' part is the integral of x*ln(x). And they just integrated by parts.

mr_coffee
Mar28-07, 04:43 PM
ahh thank you