Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.
Trending News
Binomial Expansion help!?
I have the following problem, to find the expansion of 1 divided by the square root of 1-3x, up to the terms of x^3. Also to state the values in which x is valid.
Problem:
1/√ (1-3x) up to terms of x^3
How can i expand this in binomial?
I know to do the average (a+b)^x calculations with use of the triangle, but im stomped with this...
Help will be greatly appreciated.
1 Answer
- 1 decade agoFavorite Answer
S = 1/√ (1-3x) = (1 + (-3x))^(-1/2)
Now use Newton's generalized Binomial Theorem: http://en.wikipedia.org/wiki/Binomial_theorem
You'll need to read that page to determine how the coefficients are computed as the math notation gets to difficult too reproduce in plain text.
S = 1 + (-1/2)(-3x) + (3/4)(-3x)² + (-15/8)(-3x)³ + ...
S = 1 + (3/2)x - (9/4)x² + (5/8)x³ + ...
The series converges when |1/(-3x)| < 1.
