# Thread: Arguments for complex numbers

1. ## Arguments for complex numbers

Hi everyone

For

a) - 9 = the argument is pi
9(cos pi+ isin pi)
b) 12i the arg is pi/2
12(cos (pi/2) + isin (pi/2) )

What is the argument for
a) -9
b) -12i

Anyone can help advise me? Im doing my revision...

Thank you so much.

2. $\displaystyle -9$ ? Didnt you just answer that yourself? The argument is $\displaystyle \pi$ .

$\displaystyle z = -12i$ this gives the argument $\displaystyle 12(cos(\frac{3\pi}{2})+i\cdot sin(\frac{3\pi}{2}))$

3. sorry

it was
a) 9

wats the argument for 9. thanks for the guide.

4. Originally Posted by anderson
sorry

it was
a) 9

wats the argument for 9. thanks for the guide.
If it's 9 and not -9, then the argument is 0.
9 = 9 + 0i = 9(cos 0 + i sin 0)

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