Find the exact value of sin75degrees+ sin15degrees.
One way, if you've learned some trig properties... sin x + sin y = 2*sin((x+y)/2)*cos((x-y)/2)
So sin(75) + sin(75) = 2*sin(45)*cos(30) = 2*sqrt(2)/2*sqrt(3)/2 = sqrt(6)/2
So sin(75) + sin(75) = 2*sin(45)*cos(30) = 2*sqrt(2)/2*sqrt(3)/2 = sqrt(6)/2