# #int_0^(pi/2) dx/(1+2sinx+cosx)#?

##### 1 Answer

Jul 9, 2017

After using

Also, boundaries are changed: For

Hence integrand without du became,

=

=

Thus, solution of this integral,

=

=

=

=

#### Explanation:

1) I used u=tan(x/2) transformation

2) I rewrote sinx and cosx in terms of u

3) I changed integral boundaries in terms of u

4) I simplified integrand

5) I took integral and plugged boundaries