- #1

banfill_89

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**integration by parts! MIDTERM...really quick question...please help!**

## Homework Statement

Evaluate the two following integrals:

[tex]\int[/tex] xcos5x dx and [tex]\int[/tex] ln(2x+1) dx

## Homework Equations

## The Attempt at a Solution

ok, for the first one, the answer is 1/5 x sin5x + 1/25cos5x+C

i get this answer up until the 1/5x and the 1/25...i have no idea where there coming from. in my solutions manual they come up when u take the integral of cos5x...its 1/5sin5x...where is this 1.5 coming from?

secondly the answer to the second one is: 1/2(2x+1)ln(2x+1)-x+C

again i get this exact answer except for the 1/2. i know its coming from when u take the integral of 1/(2x+1)...but i don't get where the 1/2 comes from in front of the natural log

help would be greatly appreciated...i have a midterm wednesday!