- #1

- 50

- 0

## Homework Statement

Find the modulus and argument of

1) cos(i)

2) -3i

## Homework Equations

## The Attempt at a Solution

1) So for question 1 i tried

cos(i) = ½(e

^{i2}+ e

^{-i2}) = ½(e

^{-1}+ e) . However this doesn't (as far as I can see!) lead me to the right answer. I was aiming to get it in the form re

^{ix}where r is the modulus and x the argument.

for 2) I basically just drew an argand diagram and found the radius to be 3 and the argument 3/4pi.

if you could point me in the right direction with 1 especially that would be greatly appreciated!