You are Here: Home >< Maths

Further mathematics (GCSE) Urgent help is required.

Announcements Posted on
Last day to win £100 of Amazon vouchers - don't miss out! Take our quick survey to enter 24-10-2016
1. Expand and simplify:
2x^1/2(x^1/2-x^-1/2)
I am not very sure how to solve this.
Thank you in advance fellow TSRians.
2. (Original post by Wolfram Alpha)
Expand and simplify:
2x^1/2(x^1/2-x^-1/2)
I am not very sure how to solve this.
Thank you in advance fellow TSRians.
Expand as you normally would.

And use the fact that .

Post your working if you get stuck.
3. add the outer power by the inner power of each while putting a 2 in front , 2x1X^1/2+1/2 - 2x1X^1/2+(-1/2) and simplify it to 2X-2
4. (Original post by notnek)
Expand as you normally would.

And use the fact that .

Post your working if you get stuck.
I multiplied 2x^1/2 by x^1/2 which gives 2x. Then 2x^1/2 multiplier by x^-1/2 which gives 2x^0. So would the answer just be 2x + 1?
5. (Original post by Wolfram Alpha)
I multiplied 2x^1/2 by x^1/2 which gives 2x. Then 2x^1/2 multiplier by x^-1/2 which gives 2x^0. So would the answer just be 2x + 1?
is correct.

But it should be instead of . Can you see why?

And
6. (Original post by notnek)
is correct.

But it should be instead of . Can you see why?

And
Ah, I have just noticed the negative sign. So -2x^0 gives -2 rather than zero. Thus the final answer is 2x-2. I thank you for your time. It is much appreciated.
7. (Original post by Wolfram Alpha)
Ah, I have just noticed the negative sign. So -2x^0 gives -2 rather than zero. Thus the final answer is 2x-2. I thank you for your time. It is much appreciated.
Correct
8. (Original post by regan1234567)
add the outer power by the inner power of each while putting a 2 in front , 2x1X^1/2+1/2 - 2x1X^1/2+(-1/2) and simplify it to 2X-2
9. (Original post by notnek)
Correct
I have one more question friend. (3x^1/2 - 2x^-1/2)(2x^1/2 - 3x^-1/2) equals 6x - 13 + 1/6x. Am I correct?
10. (Original post by Wolfram Alpha)
I have one more question friend. (3x^1/2 - 2x^-1/2)(2x^1/2 - 3x^-1/2) equals 6x - 13 + 1/6x. Am I correct?
Nearly but 1/6x is incorrect.

11. (Original post by notnek)
Nearly but 1/6x is incorrect.

I thought 6x^-1 was 1/6x. I am clearly wrong. Could you please enlighten me?
12. (Original post by Wolfram Alpha)
I thought 6x^-1 was 1/6x. I am clearly wrong. Could you please enlighten me?
Both are wrong but It's not clear if 1/6x means or .

Explanation :

You know that

So

It will be useful for you to become familiar with this rule :

E.g. or .
13. (Original post by notnek)
Both are wrong but It's not clear if 1/6x means or .

Explanation :

You know that

So

It will be useful for you to become familiar with this rule :

E.g. or .
Ah, I see! I was aware of that rule but I suppose I got confused when applying it. Mhmm, thanks for your help again.

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: April 27, 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

How does exam reform affect you?

From GCSE to A level, it's all changing

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

Chat with other maths applicants