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# fp1 complex numbers watch

1. (Original post by timebent)
oh ffs everytime why doesn't it go in *rips eyeballs out

http://www.examsolutions.net/a-level...e/paper.php#Q3
is k 22? no it's not i got it now

no can you do part b for me pls i don't even know what i'm doing -.-'

k=30 though
As the other user said, the way to go is algebraic division. I used (x - 1/2) as a factor but the other form is also applicable if you don't like to deal with fractions.

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2. (Original post by B_9710)
If x=1/2 is a solution then (2x-1) is a factor of the cubic.
Algebraic division is the way forward.
that's what i did but it doesn't work eventually i just get x^2 -4x+2 which doesn't give be a complex conjugate, it just gives me root 2 +2

so you'll be asking for my workings
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3. (Original post by timebent)
that's what i did but it doesn't work eventually i just get x^2 -4x+2 which doesn't give be a complex conjugate, it just gives me root 2 +2

so you'll be asking for my workings
Your very last step when doing algebraic division is wrong. You should get the quotient to be .
4. (Original post by B_9710)
Your very last step when doing algebraic division is wrong. You should get the quotient to be .
oh -.-' everytime....
5. (Original post by B_9710)
Your very last step when doing algebraic division is wrong. You should get the quotient to be .
http://www.examsolutions.net/a-level...y/paper.php#Q5

So i tried to solve for x and see what i'd get, since the question told me there'll be 2 conjugate pairs in total i should get 1 pair from this bracket on the left.

6. Sorry I was out.

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7. (Original post by timebent)
http://www.examsolutions.net/a-level...y/paper.php#Q5

So i tried to solve for x and see what i'd get, since the question told me there'll be 2 conjugate pairs in total i should get 1 pair from this bracket on the left.

Basically, anything which is negative and is square rooted.
It is basically, that number square rooted i.

I'll post examples wait.

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8. (Original post by timebent)
x

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9. (Original post by Chittesh14)
Sorry I was out.

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(Original post by Chittesh14)
Basically, anything which is negative and is square rooted.
It is basically, that number square rooted i.

I'll post examples wait.

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Thank you Thank you Thank you so much ^-^
10. Uh... .
11. (Original post by timebent)
http://www.examsolutions.net/a-level...y/paper.php#Q5

So i tried to solve for x and see what i'd get, since the question told me there'll be 2 conjugate pairs in total i should get 1 pair from this bracket on the left.

Your last step is wrong, so which are indeed conjugate pairs.
12. (Original post by Zacken)
Uh... .
You know what I meant... -16 Zacky boy.

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13. (Original post by timebent)
Thank you Thank you Thank you so much ^-^
Np. Try to follow what Zacken said and solve the second bracket.

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14. (Original post by Zacken)
Your last step is wrong, so which are indeed conjugate pairs.
oh oops i mean to put 3/2 there not the 9 and 4
thanks ^-^
(Original post by Chittesh14)
Np. Try to follow what Zacken said and solve the second bracket.

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yup...
15. (Original post by timebent)
oh oops i mean to put 3/2 there not the 9 and 4
thanks ^-^
Uh, no, that wasn't the mistake... the mistake was not including the .
16. (Original post by Zacken)
Uh, no, that wasn't the mistake... the mistake was not including the .
Oh ;_; when will i stop making these small mistakes
17. (Original post by timebent)
x
Did u manage to solve it in the end?

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18. (Original post by Zacken)
Uh, no, that wasn't the mistake... the mistake was not including the .
not sure if the method i used is called factor theorem or inspection
http://www.examsolutions.net/a-level...y/paper.php#Q5
but for this question if it gives me one complex number and there's 3 roots then i know it's got to be a pair

and i used inspection or factor theorem or whatever it's called and tried 2 and got lucky so where would i get my marks assuming that this is my working

because it has a pair

let

f(2)=8-32+44-20=0

therefore z=2 thus z-2 is a factor
19. (Original post by Chittesh14)
Did u manage to solve it in the end?

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yes i got the pair for the other bracket easily and i drew the diagram correctly
20. (Original post by timebent)
yes i got the pair for the other bracket easily and i drew the diagram correctly
Great .

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