Binomial expansion quick Qs. Watch

zee600
Badges: 0
Rep:
?
#1
Report Thread starter 4 years ago
#1
Is there a way to check the accuracy of your expansion of a binomial expression with a negative or a fractional power?
0
reply
Mr M
  • Forum Helper
Badges: 20
Rep:
?
#2
Report 4 years ago
#2
(Original post by zee600)
Is there a way to check the accuracy of your expansion of a binomial expression with a negative or a fractional power?
Substitute x = 0.01 and evaluate the first few terms and compare it to the value of the expression you are expanding?
0
reply
zee600
Badges: 0
Rep:
?
#3
Report Thread starter 4 years ago
#3
Umm...I fear not..
Thats for finding approximation of a particular constant through the binomial expansion not the accuracy of the binomial itself
(U can check if the expansion is right only if the question has a subdivision where it asks you to find the approximation of a particular constant since it would give u the right answer...
2nd) you cant substitute x=0.01 in every expression
0
reply
davros
  • Study Helper
Badges: 16
Rep:
?
#4
Report 4 years ago
#4
(Original post by zee600)
Umm...I fear not..
Thats for finding approximation of a particular constant through the binomial expansion not the accuracy of the binomial itself
(U can check if the expansion is right only if the question has a subdivision where it asks you to find the approximation of a particular constant since it would give u the right answer...
2nd) you cant substitute x=0.01 in every expression
Can you expand on what exactly it is that you want to test, i.e. give an example of a series and the value you're trying to estimate?
0
reply
zee600
Badges: 0
Rep:
?
#5
Report Thread starter 4 years ago
#5
(Original post by davros)
Can you expand on what exactly it is that you want to test, i.e. give an example of a series and the value you're trying to estimate?
Q) Expand the following binomial expression: (8-3x)^1/3

I have expanded this or any other expression of a similar type, how, in an exam do I ensure that the coefficients I have calculated are accurate?

Since expanding takes time and for me even If it looks good the answer turns out to be wrong at times: just wish to prevent that!
0
reply
davros
  • Study Helper
Badges: 16
Rep:
?
#6
Report 4 years ago
#6
(Original post by zee600)
Q) Expand the following binomial expression: (8-3x)^1/3

I have expanded this or any other expression of a similar type, how, in an exam do I ensure that the coefficients I have calculated are accurate?

Since expanding takes time and for me even If it looks good the answer turns out to be wrong at times: just wish to prevent that!
Oh right, so when you said "accuracy of expansion" you basically meant "how do I make sure my coefficients are correct?".

In general there's no quick way (unless you're dealing with positive integer exponent when you can just multiply out the brackets long-hand).

Just be careful and methodical in your working and lay things out neatly so you can re-read it easily when you come to check at the end of the exam. If you have time, of course, you can repeat the process and make sure you get the same answer as originally.
0
reply
zee600
Badges: 0
Rep:
?
#7
Report Thread starter 4 years ago
#7
Iwas hoping there d be a way...
0
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Latest
My Feed

See more of what you like on
The Student Room

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

Personalise

University open days

  • Cardiff Metropolitan University
    Undergraduate Open Day - Llandaff Campus Undergraduate
    Sat, 27 Apr '19
  • University of East Anglia
    Could you inspire the next generation? Find out more about becoming a Primary teacher with UEA… Postgraduate
    Sat, 27 Apr '19
  • Anglia Ruskin University
    Health, Education, Medicine and Social Care; Arts, Humanities and Social Sciences; Business and Law; Science and Engineering Undergraduate
    Sat, 27 Apr '19

Have you registered to vote?

Yes! (551)
37.82%
No - but I will (114)
7.82%
No - I don't want to (102)
7%
No - I can't vote (<18, not in UK, etc) (690)
47.36%

Watched Threads

View All