Respuesta :

sin^2x + cos^2x = 1 and sin^2y +cos^2 y = 1 
- so if we add the left sides of the 2 equations we get  the value 2.

Therfore it follows that
3a/2 + a^2/2 = 2

3a + a^2 = 4
a^2 + 3a - 4 = 0
(a + 4)(a - 1) = 0
The possible values of a are -4 and 1  Answer