Triple integral

[Datanaut]

Hello everyone, 

I am trying to solve this triple integral problem , but I am having some issues.

I tried with the 2 different approaches.

1.- I converted the variables to spherical coordinates, and I think it went well, until the moment to evaluate the integral using those limits (-1 , -2). I couldn't pass that. 

2.- Conversion to cylindrical coordinates, but no luck at all there. 

So, could someone be so kind in giving me some light around this? Please. Not sure if I am follow a right approach. 

 

 

 

 

[uncool]

This integral isn't meant to be evaluated in a straightforward manner. The solution is a trick.

[Datanaut]

HI - Yes thank you uncool, you are correct. The solution is a trick. 

The integral is equal to 1/3.