If z1=root2(Cos30+iSin30) and z2=root3(Cos60+iSin30)
Find Re(z1z2)

Hi Sharma, let z1 = r1 (cos A + i sin A) and z2 = r2 (cos B + i sin B)
In case of z1 * z2 = r1( cos A + i sin A) * r2 (cos B +i sin B) = r1 * r2 * [cos (A + B) + i sin (A + B) ]
Now here A = 30 and B = 60 So A + B = 90 and cos 90 = 0 and sin 90 = 1
Thereby we have z1 z2 = i (./2) (./3) * 1
So no real part. Only imaginary part is present
Hence Re (z1 *z2) = 0