http://www.mathramz.com/xyz/latexren...6b43adf795.png.

Calculate the argument and modulus for the number complex A:

http://www.mathramz.com/xyz/latexren...c8bb6144a9.png

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- Jul 24th 2009, 09:23 AMdhiabArgument and modulus
http://www.mathramz.com/xyz/latexren...6b43adf795.png

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**Calculate the argument and modulus for the number complex A:**

**http://www.mathramz.com/xyz/latexren...c8bb6144a9.png** - Jul 24th 2009, 09:49 AMJ.R
you can write:

$\displaystyle 1+e^{i\theta}=e^{i\frac{\theta}{2}}(2cos(\frac{\th eta}{2}))$

don't forget that the modulus is positive ... - Jul 24th 2009, 11:53 AMdhiab
- Jul 24th 2009, 10:07 PMJ.R
you know

$\displaystyle 0< \frac{\theta}{2} <\pi$

so,

$\displaystyle if \ \ \pi<\theta <2\pi$

then $\displaystyle 2cos(\frac{\theta}{2}+\pi)>0$

$\displaystyle (1+e^{i\theta})^n=(2cos(\frac{\theta}{2}+\pi))^ne^ {ni(\frac{\theta}{2}+\pi)}$

$\displaystyle if \ \ 0<\theta <\pi$ (it's easier than the precedent ;) )

... - Jul 25th 2009, 11:48 PMdhiab
Hello : THANK YOU

YOU HAVE 3 CASES :

http://www.mathramz.com/xyz/latexren...c28f8c02eb.png - Jul 25th 2009, 11:59 PMJ.R
wath's the point of the topic ?

it's a challenge or you don't know the solution ?

would you like help ? - Jul 26th 2009, 01:16 AMdhiab