Ask your own question, for FREE!
Mathematics 8 Online
OpenStudy (anonymous):

Express the complex number in trigonometric form -6+6√3i

OpenStudy (anonymous):

\[-6+\sqrt{3}i\]

OpenStudy (anonymous):

What are x, and y in the expression? Recall: x + iy is a form of an imaginary number.

OpenStudy (anonymous):

\[-6+6\sqrt{3}i\] sorry, i mistyped it

OpenStudy (anonymous):

Arent they just coordinates?

OpenStudy (anonymous):

doesn't matter, the same question, what are x, y?

OpenStudy (anonymous):

(-6, 6√3)?

OpenStudy (anonymous):

not that, take steps, please. you have x = -6, y = 6sqrt 3 now find r, \(r^2 = x^2 +y^2\) show me r = ??

OpenStudy (anonymous):

r=12?

OpenStudy (anonymous):

yup, now, find \(\theta\) \(tan\theta = \dfrac{y}{x}=??\)

OpenStudy (anonymous):

-30

OpenStudy (anonymous):

I got -60

OpenStudy (anonymous):

i re-did it to make sure

OpenStudy (anonymous):

ok, take your time, tag me after you get the answer

OpenStudy (anonymous):

Oh im sorry i had switched x and y

OpenStudy (anonymous):

-60 = 2pi/3 I think i remember the equation now

OpenStudy (anonymous):

nope, you have to have a logic to switch -60 to 2pi/3

OpenStudy (anonymous):

because |dw:1407542918920:dw|

OpenStudy (anonymous):

omg why do i keep making these little mistakes

OpenStudy (anonymous):

Actually, the answer is 2pi/3, but you must put some argue on that to make the solution is perfect correct.

OpenStudy (anonymous):

\[12(\cos \frac{ 5\pi }{ 3 }+isin \frac{ 5\pi }{ 3})\]

OpenStudy (anonymous):

wait what...

OpenStudy (anonymous):

That is the wrong one!!

OpenStudy (anonymous):

So 2pi/3 is right? I'm a little confused

OpenStudy (anonymous):

No confuse, =\(tan \dfrac{5\pi}{3}=tan\dfrac{2\pi}{3}= -\sqrt3\) We pick 2pi/3 because the given x = \(\color{red}{-~}6\) so that the terminal point must be in quadrant 2.

OpenStudy (anonymous):

That give us the final answer is \(12(cos\dfrac{2\pi}{3}+isin\dfrac{2\pi}{3}\)) got what I mean??

OpenStudy (anonymous):

|dw:1407543393273:dw|

OpenStudy (anonymous):

Tan=5pi/3=tan2pi/3? so why choose one over the other?

OpenStudy (anonymous):

because x = -6 , y = +6sqrt3 x <0, y>0 , the point is in quadrant 2 |dw:1407543518132:dw|

OpenStudy (anonymous):

OHHHHH

Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!
Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!