Question

Express the complex number in trigonometric form.

-3i

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

Answer 1

can you evaluate the following:
cos(180)+i sin(180)
cos(270)+i sin(270)
cos(90)+ i sin(90)
cos(0)+ i sin(0)

Answer 2

which of these will result in -i

Answer 3

cos(270)+i sin(270)

Answer 4

right cos(270)=0
and sin(270)=-1
so
3(cos(270)+i sin(270))=3(0-i)=3(-i)=-3i

Answer 5

ok thanks