Question

Express the complex number in trigonometric form.

-4

4(cos 270° + i sin 270°)
4(cos 90° + i sin 90°)
4(cos 0° + i sin 0°)
4(cos 180° + i sin 180°)

Answer 1

what do you think?

Answer 2

here your imaginary part is 0, so you have to find out for what value of theta. cos(theta) is -1 and sin(theta) is 0

Answer 3

cos 180=-1,cos 0=1,cos 90=cos 270=0