What did I get wrong in this integral?

62 Views Asked by At

$$\int \frac{(x+1)dx}{\sqrt{2x-x^2}}$$

completing the square:

$$1-(x^2-2x+1)$$ $$1-(x+1)^2$$ $$a^2-U^2$$

we have: $$U = (x+1) $$ $$a = 1$$

we have:

$$\int \frac{UdU}{\sqrt{a^2-U^2}}$$

let: $ U= a\sin\theta$ and $dU = a\cos\theta d\theta$ hence:

$$\int \frac{a\sin\theta a\cos\theta}{a\cos\theta}$$ $$ = -a\cos\theta$$ $$ = -\sqrt{2x-x^2}$$

Which is wrong, what did I miss?

1

There are 1 best solutions below

2
On BEST ANSWER

It's $1-(x-1)^2$ rather than $1-(x+1)^2$