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# fp2 transformations of complex numbers

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1. https://8dedc505ac3fba908c50836f5905...%20Edexcel.pdf

On this paper question 5 part c, why aren't we supposed to make z the subject and sub in w=u+iv as is the standard protocol for a question like this?

It is saying "A transformation T from the z-plane to the w-plane is given by"

For example on question 1 in this paper we are also solving a problem where we are putting the imaginary part = 0, but here they have done it the other way of putting z as the subject, why is it any different to this quesiton?
https://8dedc505ac3fba908c50836f5905...%20Edexcel.pdf

I hope I'm making sense

would appreciate any help

Zacken any ideas? :P
2. (Original post by Katiee224)
https://8dedc505ac3fba908c50836f5905...%20Edexcel.pdf

On this paper question 5 part c, why aren't we supposed to make z the subject and sub in w=u+iv as is the standard protocol for a question like this?

It is saying "A transformation T from the z-plane to the w-plane is given by"
Because we want to show something about z. If we re-arrange for z and then sub in u + iv, then we'll know something about the locus of w.

In this question:

We are told that Q (in the z plane) is mapped to R (in the w plane) and we are given information about R (in the w plane) and told to find information about Q (in the z plane).

In the other question:

We are told that Q (in the z plane) is mapped to R (in the w plane) and we are given information about Q (in the z plane) and told to find information about R (in the w plane)

I've used the "Q and R" in the second question even if it's not given in the question to highlight the differences. But in the second example, Q means "points on the real axis in the z-plane" and R means "line in the w-plane".
3. (Original post by Zacken)
Because we want to show something about z. If we re-arrange for z and then sub in u + iv, then we'll know something about the locus of w.

In this question:

We are told that Q (in the z plane) is mapped to R (in the w plane) and we are given information about R (in the w plane) and told to find information about Q (in the z plane).

In the other question:

We are told that Q (in the z plane) is mapped to R (in the w plane) and we are given information about Q (in the z plane) and told to find information about R (in the w plane)

I've used the "Q and R" in the second question even if it's not given in the question to highlight the differences. But in the second example, Q means "points on the real axis in the z-plane" and R means "line in the w-plane".
Aww I thought it was something along those lines but that clarifies it for me, thank you

ps you never replied to my last pm I hope your revision's going better than mine
4. (Original post by Katiee224)
Aww I thought it was something along those lines but that clarifies it for me, thank you

ps you never replied to my last pm I hope your revision's going better than mine
No problem.

Oh, I didn't? I'm sorry! I must have forgotten. It's going so-so, yours? I've pretty much just stopped all A-Level revision and I'm going all out on STEP atm so not looking forward to Physics in 6 days time... you?

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