Taylor Polynomial approximation

In summary, to obtain the number r which is an approximation to the nonzero root of the equation x^2 = sinx, we use the cubic Taylor polynomial of sinx and assume the error to be zero. This allows us to solve the equation x^2 = x - x^3/6 and find an approximation for r.
  • #1
zjhok2004
8
0

Homework Statement


obtain the number r = √15 -3 as an approximation to the nonzero root of the equation x^2 = sinx by using the cubic Taylor polynomial approximation to sinx

Homework Equations


cubic taylor polynomial of sinx = x- x^3/3!

The Attempt at a Solution


Sinx = x-x^3/3! + E(x)
x^2 = x-x^3/6+ E(x)How do I able to obtain the r?
 
Last edited:
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  • #2
In order to get exact equality you need
$$\sin(x) = x - x^3/6 + E(x)$$
where ##E(x)## is the error due to using only two terms. As an approximation, we assume this error to be zero, so we pretend that
$$\sin(x) = x - x^3/6$$
and solve the equation
$$x^2 = x - x^3/6$$
 
  • #3
jbunniii said:
In order to get exact equality you need
$$\sin(x) = x - x^3/6 + E(x)$$
where ##E(x)## is the error due to using only two terms. As an approximation, we assume this error to be zero, so we pretend that
$$\sin(x) = x - x^3/6$$
and solve the equation
$$x^2 = x - x^3/6$$
But how do I able to obtain the number r?
 
  • #4
zjhok2004 said:
But how do I able to obtain the number r?
As the problem statement says, ##r## is a nonzero root of the equation ##x^2 = \sin(x)##. You will find an approximation to this by solving the equation ##x^2 = x - x^3/6##.
 
  • #5
jbunniii said:
As the problem statement says, ##r## is a nonzero root of the equation ##x^2 = \sin(x)##. You will find an approximation to this by solving the equation ##x^2 = x - x^3/6##.
Solved, thanks!
 
Last edited:

Related to Taylor Polynomial approximation

1. What is a Taylor Polynomial approximation?

A Taylor Polynomial approximation is a mathematical method used to approximate a function using a polynomial. It is a way to represent a complex function as a simpler polynomial function, making it easier to work with and calculate values.

2. How is a Taylor Polynomial approximation calculated?

A Taylor Polynomial approximation is calculated using a formula that involves taking derivatives of the function at a specific point, and then plugging in those derivatives and the point into the formula. The more derivatives that are used, the more accurate the approximation will be.

3. Why is a Taylor Polynomial approximation useful?

A Taylor Polynomial approximation is useful because it allows us to approximate a function with a simpler polynomial function, making it easier to work with and calculate values. It also allows us to estimate the behavior of a function near a specific point.

4. What is the difference between a Taylor Polynomial approximation and a Taylor series?

A Taylor Polynomial approximation is a finite polynomial approximation of a function, while a Taylor series is an infinite polynomial representation of a function. The Taylor Polynomial approximation only uses a certain number of derivatives at a specific point, while a Taylor series uses all derivatives of a function at a specific point.

5. In what fields is Taylor Polynomial approximation commonly used?

Taylor Polynomial approximation is commonly used in fields such as physics, engineering, and economics, where complex functions need to be simplified and approximated for calculation and analysis. It is also used in computer graphics and numerical analysis.

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