Solving 31.2^(1/5) ≈ 197/99 with Binomial Expansion

In summary, the binomial expansion holds when the absolute value of x is less than 1. To approximate the value of 31.2^{\frac{1}{5}}, we can use Maclaurin series with x = 0.025.
  • #1
crays
160
0
Hi, its me again.

[tex]\left(1 - x\right)^{\frac{1}{5}}[/tex]

show that [tex]31.2^{\frac{1}{5}} \approx \frac{197}{99} [/tex]


how can i know what value should x be ?
 
Physics news on Phys.org
  • #2
In order for the binomial expansion to hold, the absolute value of x must be less than 1. In this case, since we are going to approximate it as a fraction, we would want to end up with nice simplifiable roots. This would point us towards 2^5, 32. From there, you can get x after manipulation.
 
  • #3
Still don't get it. so i let 1 - x = 32 ?

or i extract 32 out so 31.2/32 =0.975
and then let it be

[32(0.975)]^1/5
(2)(1-0.025)^1/5

then let x = 0.025?
 
  • #4
crays said:
Hi, its me again.

[tex]\left(1 - x\right)^{\frac{1}{5}}[/tex]

show that [tex]31.2^{\frac{1}{5}} \approx \frac{197}{99} [/tex]


how can i know what value should x be ?

Try Maclaurin series (=
 
  • #5
crays said:
[32(0.975)]^1/5
(2)(1-0.025)^1/5
then let x = 0.025?

Yup, that's the way to do it.
Bleh, I hate Maclaurin's lol, never use it unless necessitated.
 
  • #6
There is a forum for calculus problems. This one is for precalculus problems.
 
  • #7
I'm sorry, actually i can't differentiate which is calculus and which is not ._. In my country its just Maths S and Maths T i don't even know what it stands for. I never heard of Maclaurin series O-o
 

1. How is binomial expansion used to solve the equation 31.2^(1/5) ≈ 197/99?

Binomial expansion is a mathematical technique that allows us to expand an expression raised to a power into a polynomial. In this case, we can use binomial expansion to expand 31.2^(1/5) into a polynomial and then approximate it to the fraction 197/99.

2. What are the steps involved in using binomial expansion to solve this equation?

The first step is to rewrite the expression 31.2^(1/5) as (31.2)^(1/5). Then, we use the binomial expansion formula to expand (31.2)^(1/5) into a polynomial. Finally, we can approximate the polynomial to the fraction 197/99.

3. What is the significance of using binomial expansion to solve this equation?

Binomial expansion is a powerful tool in mathematics that allows us to approximate complex expressions into simpler ones. In this case, it allows us to solve a seemingly difficult equation involving a fractional exponent with a simple polynomial approximation.

4. Can other mathematical techniques be used to solve this equation?

Yes, there are other techniques that can be used to solve this equation, such as logarithms or using a calculator. However, binomial expansion is a more efficient and precise method for approximation.

5. How accurate is the approximation of 31.2^(1/5) to 197/99 using binomial expansion?

The approximation using binomial expansion is very accurate, with an error of less than 0.05%. This means that the value of 31.2^(1/5) is very close to 197/99, making it a reliable and efficient method for solving this equation.

Similar threads

  • Precalculus Mathematics Homework Help
Replies
7
Views
586
  • Precalculus Mathematics Homework Help
Replies
7
Views
1K
  • Precalculus Mathematics Homework Help
Replies
4
Views
735
  • Precalculus Mathematics Homework Help
Replies
10
Views
600
  • Precalculus Mathematics Homework Help
Replies
13
Views
291
  • Precalculus Mathematics Homework Help
Replies
10
Views
834
Replies
12
Views
876
  • Precalculus Mathematics Homework Help
Replies
22
Views
903
  • Precalculus Mathematics Homework Help
Replies
4
Views
1K
Back
Top