You are Here: Home >< Maths

# Argand diagram regions

Announcements Posted on
Would YOU be put off a uni with a high crime rate? First 50 to have their say get a £5 Amazon voucher! 27-10-2016
1. Hi,

I'm doing the following question:

I can do part a. Where I get a circle centre (9/8, 0), radius 3/8

I can sketch this fine, but I don't know how to plug in |z| < 3 in order to find the Region R.

I shaded in the inside of the circle but apparently its the region outside it.

Thanks,
Malc.
2. (Original post by Sir_Malc)
Hi,

I'm doing the following question:

I can do part a. Where I get a circle centre (9/8, 0), radius 3/8

I can sketch this fine, but I don't know how to plug in |z| < 3 in order to find the Region R.

I shaded in the inside of the circle but apparently its the region outside it.

Thanks,
Malc.
Literally just choose a test point that satisfies . An obvious one is , this satisfies . This is a point inside the circle .

Now where does this point map to? Well, , which is outside your -circle.

You've just shown that a point inside the z circle gets mapped to a point outside the w circle. It'd be nice if you could mark these points on your sketch to help you visualise what's going on.
3. (Original post by Zacken)
Literally just choose a test point that satisfies . An obvious one is , this satisfies . This is a point inside the circle .

Now where does this point map to? Well, , which is outside your -circle.

You've just shown that a point inside the z circle gets mapped to a point outside the w circle. It'd be nice if you could mark these points on your sketch to help you visualise what's going on.
Thankyou.

I tested a few other points and it works like you said.

Many thanks.
4. (Original post by Sir_Malc)
Thankyou.

I tested a few other points and it works like you said.

Many thanks.
Cheers! You'll only need to test one point in the actual exam.

## Register

Thanks for posting! You just need to create an account in order to submit the post
1. this can't be left blank
2. this can't be left blank
3. this can't be left blank

6 characters or longer with both numbers and letters is safer

4. this can't be left empty
1. Oops, you need to agree to our Ts&Cs to register

Updated: May 1, 2016
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Today on TSR

### University open days

Is it worth going? Find out here

Poll
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read here first

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams