- Forums
###### Help urgent maths

Watch

8 months ago

Help

For part c do I have to write all the terms out or can I use some kinda formula?? And for the rest as well is there a formula

For part c do I have to write all the terms out or can I use some kinda formula?? And for the rest as well is there a formula

(edited 8 months ago)

Reply 1

8 months ago

considering none of the sums go greater than 8 i'd assume you have to write all the terms out

from your working, though, it seems as though you've got it

from your working, though, it seems as though you've got it

Reply 2

8 months ago

Original post by AngryHomer

considering none of the sums go greater than 8 i'd assume you have to write all the terms out

from your working, though, it seems as though you've got it

from your working, though, it seems as though you've got it

But if it was a longer sequence what would I do… like if it was up to 50 😭 plz help also for this q

I got the wrong answer but idk why the black is the ms answer

(edited 8 months ago)

Reply 3

8 months ago

well because the sequence starts from 5 you can't just plug it into your formula - you need to do the (sum from 1 to 8) - (sum from 1 to 4) to get the overall sum

as for terms, it's the same as before, just plug in the numbers. i don't think they'd give it from n = 1 to 50 because that's going into further maths territory and they would have given you examples to practice on if that were the case, but identifying that it's a geometric series, as you did, is the key idea i would say.

as for terms, it's the same as before, just plug in the numbers. i don't think they'd give it from n = 1 to 50 because that's going into further maths territory and they would have given you examples to practice on if that were the case, but identifying that it's a geometric series, as you did, is the key idea i would say.

Reply 4

8 months ago

Original post by AngryHomer

well because the sequence starts from 5 you can't just plug it into your formula - you need to do the (sum from 1 to 8) - (sum from 1 to 4) to get the overall sum

as for terms, it's the same as before, just plug in the numbers. i don't think they'd give it from n = 1 to 50 because that's going into further maths territory and they would have given you examples to practice on if that were the case, but identifying that it's a geometric series, as you did, is the key idea i would say.

as for terms, it's the same as before, just plug in the numbers. i don't think they'd give it from n = 1 to 50 because that's going into further maths territory and they would have given you examples to practice on if that were the case, but identifying that it's a geometric series, as you did, is the key idea i would say.

R u sure my teacher said you can do the sequence from 5 to 8 by making the r value 4 because there’s 4 terms

Reply 5

8 months ago

Original post by Alevelhelp.1

R u sure my teacher said you can do the sequence from 5 to 8 by making the r value 4 because there’s 4 terms

okay well, just go with what your teacher says, they have a degree and i dont want to confuse you.

hope i was able to help

Reply 6

8 months ago

Original post by AngryHomer

okay well, just go with what your teacher says, they have a degree and i dont want to confuse you.

hope i was able to help

hope i was able to help

But I’m getting it wrong with her method

Reply 7

8 months ago

Original post by Alevelhelp.1

I got the wrong answer but idk why the black is the ms answer

I got the wrong answer but idk why the black is the ms answer

It looks as though you have used the formula for the infinite sum (a / (1 - r)), but what you need is S4.

Reply 8

8 months ago

Original post by Alevelhelp.1

But if it was a longer sequence what would I do… like if it was up to 50.

If you're referring to the "sin(90r)" series, you can reason that the sum of the first four terms is 1 + 0 - 1 + 0 = 0. Likewise the sum of terms u5 to u8 is also 1 + 0 - 1 + 0 = 0. Then S50 will be 12 x 0 + 1 + 0 = 1.

(edited 8 months ago)

- Medical School Requirements
- Urgent Medical school advice
- Do I need to know only 12 practicals for Science
- Hi there I’m Zainab
- Help super urgent maths
- in year grammar test (y10)
- A Level Maths advice and help
- Need urgent help
- UK school choice
- Using pencil to fill table in answer booklet for alevel further maths decision exam
- Need help with IB physics and Math
- Doing both Economics AND Business Studies for A Level?
- maths
- I need help A Level Math
- i need help on bio, chem and physics
- Stonebridge Access to HE Computer science and Maths - Unit 6 Assignment
- Very very URGENT: Is taking both Business sl and Economics hl IB okay
- Help maths a level urgent
- Help maths
- OCR chemistry a levels resources physics and maths tutor

- Official: Brunel University A100 2024 Entry Applicants
- GCSE History Study Group 2023-2024
- Could a controlling partner be good?
- a level functions help pls !!
- Official Year 11 Chat 2023-24
- Official: Imperial College London A100 2024 Entry Applicants
- EPQ interview with a professor
- Enhanced support dentistry programme
- Official University of the Arts London Applicant Thread for 2024
- DPhil evidence-based healthcare
- Is anyone applying to Universita Cattolica del Sacro Cuore (Rome) for medicine?
- EY graduate scheme 2024
- Social and health care or applied science is better in level 3
- Public Health ST1 Programme 2024 Entry Thread
- Material science interview
- Access course in Humanities and Social Science at City Lit?
- HKU / CUHK Medicine non-jupas 2024
- Girls Vs. Boys (Part 46)
- Warwick v Edinburgh
- Does anyone have Tutor2u A-Level Psychology mock papers?

- I'm almost 21 and have never been in a relationship
- Official LSE Postgraduate Applicants 2024 Thread
- TSR Community Awards 2023: Most Helpful in Universities Award - VOTING NOW OPEN
- St Andrews medicine route switch
- November 2023 Illegal Migration Intake Unit - Intake Response Team - Immigration Offi
- i wanted to experience young love :(
- The daily Wordle puzzle thread!
- Want to reach out to new friends but unsure when it is right
- EDF Grad Scheme - 2024
- MPhil Politics and International Studies 2024
- Make it More Tennis-ey !!
- World cuisines hurt/heal game
- Lancaster University
- 2024 UK Drama School Auditions
- Official KCL Offer Holders Thread for 2024 entry
- graduate entry medicine
- Muslims in Healthcare
- Official: King's College London A100 2024 Entry Applicants
- Cardiology route
- Anxiety

- UKMT Intermediate Math Challenge 2024 - Discussion
- Help with complex summation further maths a levels
- GCSE Mathematics Study Group 2023-2024
- Could I have some help with this suvat question?
- MAT practice
- A-level Mathematics Study Group 2023-2024
- Alevel Maths Question
- weird cosine question
- Series function not differentiable at a point
- hyperbolic function catenary problem

- Mock set 4 paper 2 q14 a level maths (4 distinct points)
- can anyone answer this A level vectors question (very challenging)
- STEP foundation module help pls
- Ukmt IMC 2024
- ukmt imc
- This maths question is driving me crazy
- Maths Mechanics
- Confused on surds question
- HNC MATHS A2 Task 3 (Radio Transmitters)
- Senior Maths Challenge 2023

- UKMT Intermediate Math Challenge 2024 - Discussion
- Help with complex summation further maths a levels
- GCSE Mathematics Study Group 2023-2024
- Could I have some help with this suvat question?
- MAT practice
- A-level Mathematics Study Group 2023-2024
- Alevel Maths Question
- weird cosine question
- Series function not differentiable at a point
- hyperbolic function catenary problem

- Mock set 4 paper 2 q14 a level maths (4 distinct points)
- can anyone answer this A level vectors question (very challenging)
- STEP foundation module help pls
- Ukmt IMC 2024
- ukmt imc
- This maths question is driving me crazy
- Maths Mechanics
- Confused on surds question
- HNC MATHS A2 Task 3 (Radio Transmitters)
- Senior Maths Challenge 2023

The Student Room and The Uni Guide are both part of The Student Room Group.

© Copyright The Student Room 2024 all rights reserved

The Student Room and The Uni Guide are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: Imperial House, 2nd Floor, 40-42 Queens Road, Brighton, East Sussex, BN1 3XB