Question

Complex number help?

http://i.imgur.com/Jl0m7.png

Can anyone explain how to do this?
Isn't z already in that form if the sign is changed?

Answer 1

if z= x+ iy then z bar = x-iy or is z = x - iy then z bar = x + iy :)

Answer 2

so in this case we got z bar = 9.8 + 6i

Answer 3

how does the sign change? if it was like i^2 I can understand but..

Answer 4

no that is a definition of z bar i^2 = -1 agreed but the definition of z bar = x - iy

Answer 5

only the iy changes

Answer 6

oh okay than for something like this, http://i.imgur.com/oEhiF.png
you make them 3+2i and -8-6i and add them?

Answer 7

yeah perfect

Answer 8

these are known as complex conjugates. this might help: http://www.mathwords.com/c/complex_conjugate.htm

Answer 9

so to fit the question we will get -5 -4i :)

Answer 10

thanks alot @asnaseer that was the word i was looking for "conjugates" lol

Answer 11

yw

Answer 12

awesome thanks for the help :)

Answer 13

more than welcome :)