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# fp1 complex numbers

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Why bother with a post grad course - waste of time? 17-10-2016
1. Just to clarify would the answer for the first question be X= 3, 1+/- root-1 or i all over 2?

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2. (Original post by Foreverton)
Just to clarify would the answer for the first question be X= 3, 1+/- root-1 or i all over 2?

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Yes.
3. (Original post by B_9710)
Yes.

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4. I get , i'll check.
Are you having trouble getting started?
I get .
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?
5. (Original post by B_9710)
I get , i'll check.
Are you having trouble getting started?
I get .
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?
Just summarise what you did to get to the answer in steps like an algorithm and I'll follow through.

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6. (Original post by Chittesh14)
Just summarise what you did to get to the answer in steps like an algorithm and I'll follow through.

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To begin with I found w in terms of lambda and z, from the second equation. Then I subbed in the expression for w into the first equation and just simplified. It is very fiddly and your algebra needs to be good, and make sure you don't make sign errors with the i's.
7. (Original post by Chittesh14)
That's close, sorry I was late to see this.

Attachment 563642

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Right, does using the quadratic formula work too?
8. (Original post by timebent)
Right, does using the quadratic formula work too?
Completing the square and using formula are equivalent, they both will always work for any quadratic.
9. (Original post by B_9710)
Completing the square and using formula are equivalent, they both will always work for any quadratic.
Is it quicker to complete the square?
10. (Original post by timebent)
Is it quicker to complete the square?
Depends, for simple examples it can be. But sometimes if there are square roots and complex numbers as coefficients,the quadratic formula would probably be quicker. I normally complete the square.
11. (Original post by timebent)
Is it quicker to complete the square?
I would e used the quadratic formula in the exam. It seems much faster.

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12. (Original post by B_9710)
Depends, for simple examples it can be. But sometimes if there are square roots and complex numbers as coefficients,the quadratic formula would probably be quicker. I normally complete the square.
ok thanks
(Original post by Chittesh14)
I would e used the quadratic formula in the exam. It seems much faster.

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ok
13. (Original post by B_9710)
To begin with I found w in terms of lambda and z, from the second equation. Then I subbed in the expression for w into the first equation and just simplified. It is very fiddly and your algebra needs to be good, and make sure you don't make sign errors with the i's.
Where did I go wrong...

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14. (Original post by Chittesh14)
Where did I go wrong...

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You've got it, notice there is a common factor on the numerator of .
15. (Original post by B_9710)
Depends, for simple examples it can be. But sometimes if there are square roots and complex numbers as coefficients,the quadratic formula would probably be quicker. I normally complete the square.
Ignore the last 2 steps I know they're wrong.

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17. (Original post by B_9710)
You've got it, notice there is a common factor on the numerator of .
Ignore my next 2 comments, wait where is this?

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18. (Original post by B_9710)
You've got it, notice there is a common factor on the numerator of .
Love you. Solved it, **** yes.

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19. (Original post by Chittesh14)
Love you. Solved it, **** yes.

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20. (Original post by B_9710)
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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