Find the product of the complex numbers. Express your answer in trigonometric form.

z1=5 (cos (pi/2) + i sin (pi/2))

z2=2 (cos (5pi/6) + i sin (5pi/6)),

10 (cos (4pi/3) + i sin (4pi/3)) To multiply complex numbers in trigonometric form, you simply multiply the radii and add the thetas. We have: z1=5 (cos (pi/2) + i sin (pi/2)) z2=2 (cos (5pi/6) + i sin (5pi/6)) The radii for the above 2 numbers are 5 and 2. So the result will have a radius of 5*2 = 10. The thetas are pi/2 and 5pi/6, so the new theta will be pi/2 + 5pi/6 = 3pi/6 + 5pi/6 = 8pi/6 = 4pi/3. So the answer is: 10 (cos (4pi/3) + i sin (4pi/3))