# Thread: Can somebody help me on integration?

1. ## Can somebody help me on integration?

how do i integrate this? : t / (t+88) ?? i could rewrite it like this : 1 - (88/t+88) but i dont know how to integrate that. i dont think i can substitude anything.

2. ## Re: Can somebody help me on integration?

let u = t + 88, then, du = dt,

so expression is now (u-88)/u .du, or (1 - 88/u)du

now this is simple to integrate.
dont forget to sub back in after integration

3. ## Re: Can somebody help me on integration?

Substitute u = t+88:

t = u-88
du = dt

$\int \frac {t}{t+88} dt = \int \frac {u-88}{u} du = \int (1 - \frac {88} u) du$

$= u - 88 \ln (u) = t+88-88 \ln (t+88)$

4. ## Re: Can somebody help me on integration?

thank u but i dont get how did u go from INT( 1 - 88/u ) du to u - 88*ln(u) ?
which formula did u use, i cant find it on integral table

5. ## Re: Can somebody help me on integration?

factor out 88 so u have 88(int) 1/u which is in is the natural log of u. In tables too. Please thank me

6. ## Re: Can somebody help me on integration?

oh i got it u take 88 out of integral