PLEASE HELP!!
For each complex number below, compute the modulus and argument.
1. -2i
2.-5
3.5-5i
4. 7sqrt3+7i
5.-3+4i

Question

PLEASE HELP!! 
For each complex number below, compute the modulus and argument.
1. -2i
2.-5
3.5-5i
4. 7sqrt3+7i
5.-3+4i

bluebeta · Answer

@mathmale @surjithayer

anonymous · Answer

$$|a+bi|=\sqrt{a^2+b^2}$$

anonymous · Answer

although you don't need that for the first one, since the absolute value of $-2i$ is obvious without computation

bluebeta · Answer

@satellite73 what do you mean? I know I probably sound stupid but I'm really confused.

anonymous · Answer

$-2i$ is here |dw:1458611649197:dw|

anonymous · Answer

how far is that away from the origin?

anonymous · Answer

if you are really confused, i will tell you, but it should be pretty clear how many using that is away from the origin

anonymous · Answer

"units" i meant

anonymous · Answer

if you know, let me know 
if not, let me know an i will tell you

bluebeta · Answer

its 2 units down

anonymous · Answer

yes, but of course absolute value is positive, don't worry about the direction 
so the "modulus" is 2

anonymous · Answer

what's next?

bluebeta · Answer

so r=2?

anonymous · Answer

yes, if you are calling is $r$ then $r=2$

bluebeta · Answer

ok now the argument?

anonymous · Answer

that is the angle it makes with the positive real line (like the x axis)
before we begin are you working in degrees, like $45$ and $90$ or in radians, like $\frac{\pi}{4}$ and $\frac{\pi}{2}$?