I would let or .
If , then
and our integral becomes
.
Next, let giving us
.
From this you can get the arctangent function.
Hello,
1. Substituting is indeed more thorough.
Thus the integral is :
2. Substitute
Thus the integral is :
Now you have to transform with respect to u.
Thus
And the integral is :
And from all this stuff, you can answer question b) (which is not possible with baldeagle's method).