Question

Let z and w be complex numbers such that |z| = |w| = 1, and zw is not equal to -1. Prove that
(z + w)/(zw + 1)
is a real number.

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Prove that if w,z are complex numbers such that |w|=|z|=1 and wz\=-1, then w+z/1+wz is a real number... Let z and w be complex numbers such that |z| = |w| = 1, and zw is not equal to -1. Prove that (z +...