find values of x and y complex numbers

2(x+jy)/(1-jy) +2(x+jy)/j =5(1+j)/2-j

tried everything, adding the fractions first..

mutilpying everything by 1-jy

simplifying fractions using their complex conjugates!!!

always end up with two nasty simutaeneous equations

for example now i goot

2x+2yx+y=1 and y-2x-2y^2=3

used sub

got a cubic 2y^3+y^2+2y+6 got a nasty value for y

wat do?

Reply 1

davros

16

Original post by Theafricanlegend

2(x+jy)/(1-jy) +2(x+jy)/j =5(1+j)/2-j

tried everything, adding the fractions first..

mutilpying everything by 1-jy

simplifying fractions using their complex conjugates!!!

always end up with two nasty simutaeneous equations

for example now i goot

2x+2yx+y=1 and y-2x-2y^2=3

used sub

got a cubic 2y^3+y^2+2y+6 got a nasty value for y

wat do?

It's not immediately obvious that this question can be solved given that you have 2 unknowns but only one equation!

Do you have a screenshot of the original question? Where's it from?

Reply 2

tiny hobbit

15

Original post by davros

It's not immediately obvious that this question can be solved given that you have 2 unknowns but only one equation!

Do you have a screenshot of the original question? Where's it from?

It's about complex numbers, so, assuming that x and y are supposed to be real, you can get 2 equations by equating real and imaginary parts.

Reply 3

Theafricanlegend

OP

15

Original post by davros

It's not immediately obvious that this question can be solved given that you have 2 unknowns but only one equation!

Do you have a screenshot of the original question? Where's it from?

quiz from our university online course.

I guarantee you that all it says.

i got y=-1.29995
x=-3.8333888

when subbing back into y-2x-2y^2=3 it actually gives me 3! so i guess im right sort of

Reply 4

tiny hobbit

15

Original post by Theafricanlegend

2(x+jy)/(1-jy) +2(x+jy)/j =5(1+j)/2-j

tried everything, adding the fractions first..

mutilpying everything by 1-jy

simplifying fractions using their complex conjugates!!!

always end up with two nasty simutaeneous equations

for example now i goot

2x+2yx+y=1 and y-2x-2y^2=3

used sub

got a cubic 2y^3+y^2+2y+6 got a nasty value for y

wat do?

You're doing better than me, my approach led me to an equation in y^5.