# A little integration problem.

1. Apr 15, 2009

### Noo

Solved. Thanks.

Last edited: Apr 15, 2009
2. Apr 15, 2009

### meiso

The simplest way to solve that indefinite integral is to realize that

$$\frac{d}{dx}tan x = sec^{2}x$$ , and try a u-substitution from there...

3. Apr 15, 2009

### Noo

Yes, sorry, i am stupid. I realised that 2 minutes after posting here. I'm pretty sure i have it now. It's just -(2+u)^{-1} for u=tanx, right? And thanks for the reply.

4. Apr 15, 2009

### meiso

No problem. And, actually, you can set u = tan(x) + 2 to make things even easier. 2 is just a constant, so the derivative of tan(x) is the same as the derivative of tan(x) + 2.

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