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°)

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°)

anonymous · Answer

@arose114 I believe it's C.

anonymous · Answer

Thank you!

anonymous · Answer

@GLKK you're not suppose to give straight answers people ask questions because they don't understand something please don't give answers without explaining or walk them through so they can engage in solving

jim_thompson5910 · Answer

the answer is wrong anyway

jdoe0001 · Answer

well... notice the coordinates $\large { -3i\implies 0-3i\implies (x,y)
\ \quad \

\begin{array}{llll}
0&-3\
x&y
\end{array} }$    
graph that... what angle does it give you?

anonymous · Answer

270

anonymous · Answer

so B?

anonymous · Answer

http://www.ditutor.com/complex_numbers/trigonometric_form.html heres a website that might help understanding

jdoe0001 · Answer

yeap    270  and the "r" is well... |-3|    so |dw:1407455167738:dw|

anonymous · Answer

Ahh okayy!!! Thank you so much!

jdoe0001 · Answer

r is really just the hypotenuse of x, y   so    $\bf r=\sqrt{x^2+y^2}\implies r\sqrt{0+3^2}\to 3$

jdoe0001 · Answer

yw