convert 3 - 3i to polar form.

a. ‘3sqrt(2)”cis” (pi)/4’

b. ‘3sqrt(2)”cis” (3pi)/4’

c. ‘3sqrt(2)”cis” (5pi)/4’

d. ‘3sqrt(2)”cis” (7pi)/4’

Respuesta :

Answer:

Option d is correct that is [tex]z=\sqrt{18} cos(\frac{7\pi}{4})+i sin(\frac{7\pi}{4})[/tex]

Step-by-step explanation:

We have been given a complex number 3-3i we have to convert it in the polar form:

polar form of a complex number:

[tex]z=r(cos{\theta}+i sin{\theta})[/tex]

Where, [tex]r=\sqrt{x^2+y^2}[/tex]

the general form of complex number is:

x+iy

Here, x=3 and y=-3

Hence, [tex]r=\sqrt{3^2+(-3)^2}=\sqrt{18}[/tex]

And [tex]\theta=tan^{-1}\frac{y}{x}[/tex]

   [tex]\theta=tan^{-1}\frac{-3}{3}[/tex]

[tex]\Rightarrow \theta=tan^{-1}(-1)[/tex]

[tex]\Rightarrow \theta=2{\pi}-\frac{\pi}{4}[/tex]

[tex]\Rightarrow \theta=\frac{7\pi}{4}[/tex]

Hence, substituting all the values in polar form formula we get:

[tex]z=\sqrt{18} cos(\frac{7\pi}{4})+i sin(\frac{7\pi}{4})[/tex]

Therefore, option d is correct.

Q&A Education