Turn on thread page Beta
 You are Here: Home >< Maths

# how does this work? watch

1. (Original post by steve2005)
My answer to the OP is that the negative disappears because of the modulus sign, and that is the only reason.
Yes. The OP said that, and nuodai agreed with him, and then went on to say something further.
2. Maths wars. Who is correct? find out next week.
3. Looking at nuodai post again I can see that I was wrong to criticise .

I misread his post in that i did not take account of "any more"

I agree that the modulus makes the expression positive and that since both numerator and denominator are squares then brackets can be used rather than the modulus sign.

Edit: I was wrong to bow to pressure , the blue brackets should be replaced by the modulus sign. Note posts 24 and 25.
4. (Original post by steve2005)
Right, , I'll agree with you there. And also , because what's in the modulus is always positive. However, it's not true that ; take as an example... this is because you have to take the positive square root, so you have to put a modulus back in again, giving you .

I didn't follow the rest of the thread, so if I'm not addressing anything here let me know.
5. (Original post by nuodai)
Right, , I'll agree with you there. And also , because what's in the modulus is always positive. However, it's not true that ; take as an example... this is because you have to take the positive square root, so you have to put a modulus back in again, giving you .

I didn't follow the rest of the thread, so if I'm not addressing anything here let me know.

I agree with you 100%

Two sentences deleted because they contained wrong material.
6. (Original post by steve2005)
The modulus sign should be used throughout the entire problem and hence the use of square brackets is wrong.
There's no reason why the modulus sign should be used when what's within it is always positive. Like, if , there'd be no point writing when you can write , but you would need to write if you were going to take the power of 2 outside the log. It doesn't really matter though; I mean the modulus sign does no harm, but it needn't be there for the sake of it Where have you got this idea from?
7. (Original post by nuodai)
There's no reason why the modulus sign should be used when what's within it is always positive. Like, if , there'd be no point writing when you can write , but you would need to write if you were going to take the power of 2 outside the log. It doesn't really matter though; I mean the modulus sign does no harm, but it needn't be there for the sake of it Where have you got this idea from?
I agree.

Reply
Submit reply
Turn on thread page Beta

### Related university courses

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:
Updated: July 19, 2009
Today on TSR

### Edexcel C4 Maths Unofficial Markscheme

Find out how you've done here

### 1,135

students online now

Exam discussions

Poll
Useful resources

## Make your revision easier

### Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams

Can you help? Study help unanswered threads

## Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.