# Maths help?Watch

Announcements
#1
Not to sound stupid but I was wondering if -½ is the same as -1/-2

And also, I was watching this indices revision video, and the person said 2x∧-3 = 2/x³ I would have thought 2x^-3 would be 1/2x^3 ?

This is the same for 3x²y∧-³ where they said it equals 3x²/y³
0
3 years ago
#2
(Original post by cicelym)
Not to sound stupid but I was wondering if -½ is the same as -1/-2

And also, I was watching this indices revision video, and the person said 2x∧-3 = 2/x³ I would have thought 2x^-3 would be 1/2x^3 ?

This is the same for 3x²y∧-³ where they said it equals 3x²/y³
No, -½isn't the same as -1/-2 because -1/-2 equals a 0.5 because two negatives divided by each other equal a positive whereas -½ is equal to -0.5.

tbh I'm entirely sure but i think the negative sign applies to the whole answer of 1/2. So Although 1/2 = 0.5, the negative of 0.5 is obviously -0.5.

And the video seems to be wrong... I also agree 2x∧-3 is 1/2x^3.
0
#3
(Original post by BTAnonymous)
No, -½isn't the same as -1/-2 because -1/-2 equals a 0.5 because two negatives divided by each other equal a positive whereas -½ is equal to -0.5.

tbh I'm entirely sure but i think the negative sign applies to the whole answer of 1/2. So Although 1/2 = 0.5, the negative of 0.5 is obviously -0.5.

And the video seems to be wrong... I also agree 2x∧-3 is 1/2x^3.

Ah ok I see thank you
0
3 years ago
#4
The guy in the video is correct. 2x^3 means

2 multiplied by x^-3 = 2 multiplied by 1/x^3
= 2/x^3

This is because only the 'x' is to the power of -3 the 2 is not to the power of -3 there is a separation between the 'x' and the 2 and according to BIDMAS the index (power) comes before the multiplication.

Hope this helped xx
0
3 years ago
#5
(Original post by cicelym)
Ah ok I see thank you
Ahhh.... I see our mistake...

I guess the 1 which comes from x^-5 is because the coefficient of x is 1. Therefore, 2x^-3 is 2/3x^3 because the coefficient of x is 2. Well I've learnt another new thing today!
0
X

new posts

### 2,848

people online now

### 225,530

students helped last year
Latest
My Feed

### Oops, nobody has postedin the last few hours.

Why not re-start the conversation?

see more

### See more of what you like onThe Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

### University open days

• Bournemouth University
Wed, 21 Aug '19
• University of Dundee
Mon, 26 Aug '19
• University of Aberdeen
Tue, 27 Aug '19

### Poll

Join the discussion

At least 5 GCSEs at grade 4 (63)
14.96%
At least 5 GCSEs at grade 5 (63)
14.96%
At least 5 GCSEs at grade 6 (78)
18.53%
Higher than 5 GCSEs at grade 6 (170)
40.38%
Pass in English and Maths GCSE (20)
4.75%
6.41%