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fp1 complex numbers

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Reply 40
Avatar for B_9710
B_9710
18
Original post by Chittesh14
I've got another question, but I really can't be asked. Maths is just ****ing long in this review exercise. Each question takes ages lol (and the amount of times I get each question wrong makes it worse)...


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Post it if you're unsure and I will take a look.
Original post by B_9710
Post it if you're unsure and I will take a look.


Meh, in bed now. Tomorrow :smile:
Reply 42
Avatar for timebent
timebent
OP
2
Original post by Chittesh14
Anyone, is there a faster way?

It's meant to be part (c)


halp what did i do wrong?

A3+i+B1−i=1+3+0i\dfrac{A}{\sqrt 3 +i} + \dfrac{B}{1-i}=1+ \sqrt 3 +0i

A(3−i)4+B(1+i)2=1+3+0i\dfrac{A(\sqrt3 -i)}{4} +\dfrac{B(1+i)}{2}=1+\sqrt 3 +0i

A3−Ai+2B+2Bi4=1+3+0i{A\sqrt 3 -Ai+2B+2Bi}{4}=1+\sqrt 3 +0i

Unparseable latex formula:

\dfrac{A\sqrt 3 +2B}{4} +\dfrac{2Bi-Ai}{4}}=1+\sqrt 3 +0i



2B−A4=0\dfrac{2B-A}{4}=0

2B=A2B=A

A3+A4=1+3\dfrac{A\sqrt 3 +A}{4}=1+\sqrt 3

A3+A=1+34A\sqrt 3 +A=\dfrac{1+\sqrt 3}{4}

A(1+3)=1+34A(1+\sqrt 3)=\dfrac{1+\sqrt 3}{4}

A=14A=\dfrac{1}{4}

B=12B=\dfrac{1}{2}
Reply 43
Avatar for timebent
timebent
OP
2
Original post by B_9710
I get z=1+λi z=1+\lambda i , i'll check.
Are you having trouble getting started?
I get w=λ+i w=\lambda + i .
My method was quite long but with these answers coming out so nicely it looks right, although I haven't checked.
EDIT. These are correct.
Do you need a hand on how to start?


Do you not need to find λ\lambda?
Original post by timebent
halp what did i do wrong?

A3+i+B1−i=1+3+0i\dfrac{A}{\sqrt 3 +i} + \dfrac{B}{1-i}=1+ \sqrt 3 +0i

A(3−i)4+B(1+i)2=1+3+0i\dfrac{A(\sqrt3 -i)}{4} +\dfrac{B(1+i)}{2}=1+\sqrt 3 +0i

A3−Ai+2B+2Bi4=1+3+0i{A\sqrt 3 -Ai+2B+2Bi}{4}=1+\sqrt 3 +0i

Unparseable latex formula:

\dfrac{A\sqrt 3 +2B}{4} +\dfrac{2Bi-Ai}{4}}=1+\sqrt 3 +0i



2B−A4=0\dfrac{2B-A}{4}=0

2B=A2B=A

A3+A4=1+3\dfrac{A\sqrt 3 +A}{4}=1+\sqrt 3

A3+A=1+34A\sqrt 3 +A=\dfrac{1+\sqrt 3}{4}

A(1+3)=1+34A(1+\sqrt 3)=\dfrac{1+\sqrt 3}{4}

A=14A=\dfrac{1}{4}

B=12B=\dfrac{1}{2}


I'm lost after your third step lol, you should still have it all divided by 4.


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Original post by timebent


A3+A=1+34A\sqrt 3 +A=\dfrac{1+\sqrt 3}{4}
]



Check this step again, look at your previous step.

It should be multiplied by 4, but it's divided by 4. Now, if you think of that in ratio 4 / 0.25 = 16.
Hence, the correct answers will be obtained if you multiply those. Skies by 16 and that's correct because A= 4 and B = 2

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(edited 7 years ago)
Reply 46
Avatar for timebent
timebent
OP
2
Original post by Chittesh14
Check this step again, look at your previous step.

It should be multiplied by 4, but it's divided by 4. Now, if you think of that in ratio 4 / 0.25 = 16.
Hence, the correct answers will be obtained if you multiply those. Skies by 16 and that's correct because A= 4 and B = 2

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oops -.-

at least i got multiples :biggrin: it's something xD
Original post by timebent
x


You may look at this if you feel you need to.

ImageUploadedByStudent Room1469198969.005790.jpg


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(edited 7 years ago)
Reply 48
Avatar for B_9710
B_9710
18
Original post by timebent
Do you not need to find λ\lambda?


No.
Original post by timebent
oops -.-

at least i got multiples :biggrin: it's something xD


I appreciate your effort, you've done everything right except forgot how to get rid of the denominator of a fraction :biggrin:. At least you've got the hard stuff right which is actually applying the knowledge from FP1 of complex conjugates and denominators which contain complex numbers.


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Original post by B_9710
X.


20(b) please.. 💙

ImageUploadedByStudent Room1469199194.089056.jpg


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Reply 51
Avatar for timebent
timebent
OP
2
Original post by Chittesh14
You may look at this if you feel you need to.

ImageUploadedByStudent Room1469198969.005790.jpg


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yea that last few steps thanks ^-^ phew i feel as if i know everything already xD
Original post by B_9710
No.

oh, so the bit where it says a and b are functions of λ\lambda tells me i don't need to find it?
Original post by Chittesh14
I appreciate your effort, you've done everything right except forgot how to get rid of the denominator of a fraction :biggrin:. At least you've got the hard stuff right which is actually applying the knowledge from FP1 of complex conjugates and denominators which contain complex numbers.


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awesome my basic maths always lets me down somewhere like a minus or plus -.- really need to sort it out haha
Original post by B_9710
X.


Ignore my question, I kept writing 9 as q lmao.


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Original post by timebent
yea that last few steps thanks ^-^ phew i feel as if i know everything already xD

oh, so the bit where it says a and b are functions of λ\lambda tells me i don't need to find it?


awesome my basic maths always lets me down somewhere like a minus or plus -.- really need to sort it out haha


If you keep posting on this thread and getting help from me and the other user who is a genius, then - soon - you will know everything.

I love to help you because you're learning something I was learning a week ago. So, you're helping me recap and test my knowledge - reinforcing it. It just makes it easier for me, so I have to revise less again after I finish :smile:.
.
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Reply 54
Avatar for timebent
timebent
OP
2
Original post by Chittesh14
If you keep posting on this thread and getting help from me and the other user who is a genius, then - soon - you will know everything.

I love to help you because you're learning something I was learning a week ago. So, you're helping me recap and test my knowledge - reinforcing it. It just makes it easier for me, so I have to revise less again after I finish :smile:.
.
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Awesome, so soon after i do a bunch of question and get most of them right i can move on and learn more :biggrin:
Original post by timebent
Awesome, so soon after i do a bunch of question and get most of them right i can move on and learn more :biggrin:


Yeah, hopefully :smile:. I can post questions too once you feel you've mastered it. This is just to see if you have because I must've encountered a few difficult questions too.v

If you have any concerns regarding questions, just keep posting them here like you've been doing so. As you can see, it's worth it for all of us.

And, you have to get ALL OF THEM right. That's what we're here for, just get every single one correct. Don't take any risk. Let no question defeat you.


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Reply 56
Avatar for timebent
timebent
OP
2
Original post by Chittesh14
Yeah, hopefully :smile:. I can post questions too once you feel you've mastered it. This is just to see if you have because I must've encountered a few difficult questions too.v

If you have any concerns regarding questions, just keep posting them here like you've been doing so. As you can see, it's worth it for all of us.

And, you have to get ALL OF THEM right. That's what we're here for, just get every single one correct. Don't take any risk. Let no question defeat you.


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oops... o.o already let one do me in, forgot how to do roots of equation but i know for this time :biggrin:

also are you allowed a calculator for fp1?
Original post by timebent
oops... o.o already let one do me in, forgot how to do roots of equation but i know for this time :biggrin:

also are you allowed a calculator for fp1?


Lol no worries, if you still remember that question - attempt it and if you still struggle, post it here.
And yeah, you are allowed a calculator. Of course bro, no one will remember the arc tan of 1.2345 by heart xD etc.

You'll also see in Chapter 2 why a calculator is so handy lol... Even though it does your head in inputting masses of numbers, it's a fun chapter - relatively quick other than the long ass questions.


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Reply 58
Avatar for timebent
timebent
OP
2
Original post by Chittesh14
Lol no worries, if you still remember that question - attempt it and if you still struggle, post it here.
And yeah, you are allowed a calculator. Of course bro, no one will remember the arc tan of 1.2345 by heart xD etc.

You'll also see in Chapter 2 why a calculator is so handy lol... Even though it does your head in inputting masses of numbers, it's a fun chapter - relatively quick other than the long ass questions.


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oh ffs everytime why doesn't it go in *rips eyeballs out

http://www.examsolutions.net/a-level-maths-papers/Edexcel/Further-Maths/Further-Maths-FP1/2013-June/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
(edited 7 years ago)
Reply 59
Avatar for B_9710
B_9710
18
Original post by timebent
oh ffs everytime why doesn't it go in *rips eyeballs out

http://www.examsolutions.net/a-level-maths-papers/Edexcel/Further-Maths/Further-Maths-FP1/2013-June/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


If x=1/2 is a solution then (2x-1) is a factor of the cubic.
Algebraic division is the way forward.

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