How do you find the exact value of sin(75 degrees )?

Sin(75) = sin (45 +30)

trig identity :  sin (x+y) = sinx cosy +cosxsiny

sin(45+30) = sin45cos30 + cos45sin30

                  = (sqrt2 /2)(sqrt3 /2) + (sqrt 2 /2 * 1/2)

                 = ( sqrt 6) /4  +  sqrt 2/4

                   1/4 (sqrt 6 + sqrt 2)