Question

`sin^2(45^@)+ sin^2(30^@)+ sin^2(60^@)+ sin^2(90^@)= ( - 5)/( 4)`?

Answer 1

Please see below.

Explanation:

`rarrsin^2(45°)+sin^2(30°)+sin^2(60°)+sin^2(90°)`

`=(1/sqrt(2))^2+(1/2)^2+(sqrt(3)/2)^2+(1)^2`

`=1/2+1/4+3/4+1`

`=1/2+2=5/2`