Question

If z1 = 12(cos55° + isin55°) and z2 = 4(cos95° + isin95°), then |z1z2|= ???

Answer 1

when multiplying complex numbers in polar form
multiply the "r" and add the angles

\[z_1 z_2 = 48 [\cos(55+95) +i \sin(55+95)]\]
of course the magnitude is just the "r" so:
\[|z_1 z_2| = 48\]