You are Here: Home >< Maths

# maths help watch

2. (Original post by mervin101)
Thread moved to maths. Please post in the maths forum for maths subject questions, thanks

For this question, can you tell us what you've tried and post your working?
3. (Original post by mervin101)
The difference between and is the same as the difference between and
4. (Original post by RDKGames)
The difference between and is the same as the difference between and
is that something i have to remember?
5. (Original post by mervin101)
is that something i have to remember?
Of course. That's a fundamental property of an arithmetic sequence - the difference between each term is the same.
6. (Original post by RDKGames)
Of course. That's a fundamental property of an arithmetic sequence - the difference between each term is the same.

so i wrote out this:
u3-u2 = u2-u1

so

(4k+1) - (2k+5) = (2k+5) - (k-2)

obviously i have to show k=11 so do I group the k terms and numbers?
7. (Original post by mervin101)
so i wrote out this:
u3-u2 = u2-u1

so

(4k+1) - (2k+5) = (2k+5) - (k-2)

obviously i have to show k=11 so do I group the k terms and numbers?
Yes, just solve for k.
8. (Original post by RDKGames)
Yes, just solve for k.
i have done A but how do i do b? is it differentiation? does f''(x) mean differentiate second principle

9. (Original post by mervin101)
i have done A but how do i do b? is it differentiation? does f''(x) mean differentiate second principle
denotes the second derivative of - which can be equivalently called to be the first derivative of . So yes just differentiate again.
10. (Original post by RDKGames)
denotes the second derivative of - which can be equivalently called to be the first derivative of . So yes just differentiate again.
thanks
i got f''(x) = 8+2x^-3

so that ^ was the second differential but what was the first? was it the function given? or 8x - x^-2 ?
11. (Original post by mervin101)
thanks
i got f''(x) = 8+2x^-3

so that ^ was the second differential but what was the first? was it the function given? or 8x - x^-2 ?
The first derivative is given by as I told you so yes it is , but if you meant what the original function is, you need to integrate the first derivative function.
12. (Original post by RDKGames)
The first derivative is given by as I told you so yes it is , but if you meant what the original function is, you need to integrate the original function.

i understand now thank you

for c) to find f(x) do i integrate 8x-x^-2?

its 7 marks and im clueless
13. (Original post by mervin101)
i understand now thank you

for c) to find f(x) do i integrate 8x-x^-2?

its 7 marks and im clueless
Yes..
14. (Original post by RDKGames)
Yes..
but i dont understand the question
at first i thought "determine an equation of the curve" meant use the equation of a line (y-y1=m(x-x1)
15. y-y1=m(x-x1) is for finding the equation of a line. The question wants you to find the formula of a curve.
As y=f(x) you can the equation of the curve by integrating f'(x).
16. (Original post by TheFirstOrder)
y-y1=m(x-x1) is for finding the equation of a line. The question wants you to find the formula of a curve.
As y=f(x) you can the equation of the curve by integrating f'(x).
Understood. So generally when I am asked to find the equation of a curve must I integrate?
17. (Original post by mervin101)
Understood. So generally when I am asked to find the equation of a curve must I integrate?
Depends on the context.

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: February 7, 2017
Today on TSR

### 10,400 people unaware they have HIV

Have you been tested?

### University open days

• University of Roehampton
Sat, 17 Nov '18
• Edge Hill University
Faculty of Health and Social Care Undergraduate
Sat, 17 Nov '18
• Bournemouth University
Sat, 17 Nov '18
Poll
Useful resources

### 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