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

Answer 1

@mathmale @surjithayer

Answer 2

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

Answer 3

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

Answer 4

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

Answer 5

\(-2i\) is here

Answer 6

how far is that away from the origin?

Answer 7

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

Answer 8

"units" i meant

Answer 9

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

Answer 10

its 2 units down

Answer 11

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

Answer 12

what's next?

Answer 13

so r=2?

Answer 14

yes, if you are calling is \(r\) then \(r=2\)

Answer 15

ok now the argument?

Answer 16

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 \(\frac{\pi}{2}\)?