integrate:dz/(z^2+1)

Question

where z is a complex number.....plz working

Answer 1

this is a standard form.

Let
z = tanθ
z^2+1 = sec^2θ
dz = sec^2θ dθ

Plug that in and see how simple it is.

You can also use

z = sinhθ

but that's less common.

Answer 2

what the meaning of that box

Answer 3

Hmmm. font problem, I guess. It's theta.

Let's use t

z = tan(t)
z^2+1 = sec^2(t)
dz = sec^2(t) dt