4U Complex Numbers Help! (1 Viewer)

[Alkanes]

Ok guys im stuck on this question

Given that x and y are real, and that (2+i) is a root of the equation



Find the values of x and y

 

[hscishard]

looks like you put it in then equate the real and imaginary parts =0. Then you might need to solve simulatenously.
Sorry for not doing the question lol

 

[Alkanes]

Haha ok. Anyone bothered?

 

[Shadowdude]

looks like you put it in then equate the real and imaginary parts =0. Then you might need to solve simulatenously.
Sorry for not doing the question lol

^ That is how.

You're 4u, that's how you do it - so you don't need someone to do it for you as I feel it ruins the joy of figuring it out and getting the answer yourself.

 

[Alkanes]

I just started so i'm not totally that confident

 

[Shadowdude]

Build your confidence now. gogogogog

We already told you how to solve it anyway... go try and if there's still trouble come back - methinks.

 

[hscishard]

okay if you just started, then the thoughts you should have are:
(2+i) is a root, if I sub it in LHS will =0

Next, after the expansions you will have a BIG complex number. RHS says it's 0, therefore the real part is 0 and the imaginary part is 0. By doing so, you will get some function, maybe y in terms of x, or y = number x = number.

 

[Alkanes]

Ahh ok much clearer clarification. I will try it =) Thanks for your help

 

[SpiralFlex]

Okay, it seems that Alkane's worksheet may have the wrong answer as he has told me. Anyone want to check my working?

The answers at the back say, , for him.








Equation 1:

Equation 2:









Also, why are all Prelim student's doing Complex numbers today?!

 

[Hermes1]

Okay, it seems that Alkane's worksheet may have the wrong answer as he has told me. Anyone want to check my working?

The answers at the back say, , for him.








Equation 1:

Equation 2:








Also, why are all Prelim student's doing Complex numbers today?!

yep thats what i got

SpiralFlex your owning 4 unit already

 

[SpiralFlex]

yep thats what i got

SpiralFlex your owning 4 unit already

So B.O.B was wrong then.

 

[Hermes1]

So B.O.B was wrong then.

whats B.O.B?

well this sort of question its really easy to make a mistake. but these r easy marks you want to nail in your trial

 

[Alkanes]

Thank You Spi like always. Yep B.O.B was wrong.

 

[SpiralFlex]

whats B.O.B?

well this sort of question its really easy to make a mistake. but these r easy marks you want to nail in your trial

Back Of Book.

 

[Hermes1]

Back Of Book.

ah tnks.

 

[AAEldar]

whats B.O.B?

well this sort of question its really easy to make a mistake. but these r easy marks you want to nail in your trial

Not gonna lie, I made a mistake when I did it hahaha.

I left out a minus sign >.<

 

[SpiralFlex]

Not gonna lie, I made a mistake when I did it hahaha.

I left out a minus sign >.<

ME TOO! I left out minus sign for 2.5.