prove the integration

Limit from -2 to -1 and 1 to 2 will have f(x) = x² - 1 and for Limit -1 to 1 , f(x) = 1 - x² ,

 

So I = limit(-1 to 1) [x - x³/3] + Limit(-2 to -1 , 1 to 2) [x³/3 - x] 

 

= 4