The value of sin 1050.sin750 is
If y=sin21500∘+4sin4750∘−4sin2750∘cos2750∘4−sin21500∘−4sin2750∘. Then the value of 9y is ___
y = sin21500∘+4sin4750∘−4sin2750∘cos2750∘4−sin21500∘+4sin2750∘ Find the value of 9y.
If 3 cosx+ 2cos3x = cosy, 3sinx+2sin3x=siny, then the value of 4(cos2x)2 is