Express the complex number in trigonometric form.

-4i

Question

Express the complex number in trigonometric form. 

-4i

anonymous · Answer

-4i = 4(cos(3Pi/2)+i sin(3Pi/2))

anonymous · Answer

these are my answer choices?
 4(cos 180° + i sin 180°)

 4(cos 270° + i sin 270°)

 4(cos 90° + i sin 90°)

 4(cos 0° + i sin 0°)

anonymous · Answer

3Pi/2 = 270º
so
4(cos 270° + i sin 270°)

anonymous · Answer

oohh okay duhh, thank you!! could you help me on another if u have a min?

anonymous · Answer

k

anonymous · Answer

Express the complex number in trigonometric form. 

5 - 5i 

i thought the answer was 5sqrt2(cos5pi/4+isin5pi/4)

anonymous · Answer

??

anonymous · Answer

put it this way:
5(1-i)
what do you think now?

anonymous · Answer

wait? huh

anonymous · Answer

|dw:1362519390105:dw|

anonymous · Answer

these are the answer choices;

5sqrt2(cos5pi/4+isin5pi/4)

5sqrt2(cos7pi/4+isin7pi/4)

5(cos5pi/4+isin5pi/4)

5(cos7pi/4+isin7pi/4)

anonymous · Answer

|dw:1362519465562:dw|
what is this angle