By using spherical coordinates , find the volume bounded sides by plane (x^2) + (y^2) +(z^2) =4 , above by sqrt ( x^2 + y^2 ) , below by plane z = 0 ...

Calculus III - Spherical Coordinates

I'm having problem finding my Φ .... Here's my diagram ... The shaded part represent the volume bounded... i have let the limit of Φ from 0 to (π- π/4) = 3π/4 , but still couldnt get the ans