Question

Write the complex number in the form a + bi.

3(cos 270° + i sin 270°)

Could someone please explain how to do problems like these?

Answer 1

Just evaluate cos(270) and sin(270) and do any simplifying.

Answer 2

3(0+-1i)=0-3i=-3i
is this what you looking for?

Answer 3

@burn23 yes!

Answer 4

\(\large \tt \begin{align} \color{black}{z=a+bi\\~\\
r=|z|=\sqrt{a^2+b^2}\\~\\
\alpha=tan^{-1}(\dfrac{b}{a})\\~\\
trig form \\~\\
z=r(cos\alpha+isin\alpha)\\~\\

} \end{align}\)

Answer 5

go reverse

Answer 6

you gone give me a medal?:)