Math Problem Statement

Solve

Given function y = 5x^5 + 4x^4 + 3x^3 + 2x^2 + x + 1 and that the value of the function at x = 1 is 16, calculate the function value at x = 2 using the Taylor series expansion (up to the fifth term only).

Solution

To solve this problem, we will use the Taylor series expansion for the given function y=5x5+4x4+3x3+2x2+x+1y = 5x^5 + 4x^4 + 3x^3 + 2x^2 + x + 1, around x=1x = 1, and calculate the value at x=2x = 2. The Taylor series expansion of a function f(x)f(x) around aa is given by:

f(x)f(a)+f(a)(xa)+f(a)2!(xa)2+f(a)3!(xa)3+f(4)(a)4!(xa)4+f(5)(a)5!(xa)5+f(x) \approx f(a) + f'(a)(x - a) + \frac{f''(a)}{2!}(x - a)^2 + \frac{f'''(a)}{3!}(x - a)^3 + \frac{f^{(4)}(a)}{4!}(x - a)^4 + \frac{f^{(5)}(a)}{5!}(x - a)^5 + \ldots

We need to find the derivatives of the function up to the fifth order and evaluate them at x=1x = 1.

  1. Calculate f(1)f(1): Given that f(1)=16f(1) = 16.

  2. Find the derivatives of f(x)f(x): f(x)=5x5+4x4+3x3+2x2+x+1f(x) = 5x^5 + 4x^4 + 3x^3 + 2x^2 + x + 1

    • First derivative, f(x)=25x4+16x3+9x2+4x+1f'(x) = 25x^4 + 16x^3 + 9x^2 + 4x + 1
    • Second derivative, f(x)=100x3+48x2+18x+4f''(x) = 100x^3 + 48x^2 + 18x + 4
    • Third derivative, f(x)=300x2+96x+18f'''(x) = 300x^2 + 96x + 18
    • Fourth derivative, f(4)(x)=600x+96f^{(4)}(x) = 600x + 96
    • Fifth derivative, f(5)(x)=600f^{(5)}(x) = 600
  3. Evaluate the derivatives at x=1x = 1:

    • f(1)=25(1)4+16(1)3+9(1)2+4(1)+1=25+16+9+4+1=55f'(1) = 25(1)^4 + 16(1)^3 + 9(1)^2 + 4(1) + 1 = 25 + 16 + 9 + 4 + 1 = 55
    • f(1)=100(1)3+48(1)2+18(1)+4=100+48+18+4=170f''(1) = 100(1)^3 + 48(1)^2 + 18(1) + 4 = 100 + 48 + 18 + 4 = 170
    • f(1)=300(1)2+96(1)+18=300+96+18=414f'''(1) = 300(1)^2 + 96(1) + 18 = 300 + 96 + 18 = 414
    • f(4)(1)=600(1)+96=696f^{(4)}(1) = 600(1) + 96 = 696
    • f(5)(1)=600f^{(5)}(1) = 600
  4. Substitute these values into the Taylor series expansion up to the fifth term: f(2)16+55(21)+1702!(21)2+4143!(21)3+6964!(21)4+6005!(21)5f(2) \approx 16 + 55(2-1) + \frac{170}{2!}(2-1)^2 + \frac{414}{3!}(2-1)^3 + \frac{696}{4!}(2-1)^4 + \frac{600}{5!}(2-1)^5 f(2)16+55+1702+4146+69624+600120f(2) \approx 16 + 55 + \frac{170}{2} + \frac{414}{6} + \frac{696}{24} + \frac{600}{120} f(2)16+55+85+69+29+5f(2) \approx 16 + 55 + 85 + 69 + 29 + 5 f(2)259f(2) \approx 259

Hence, the estimated value of the function at x=2x = 2 using the Taylor series expansion up to the fifth term is 259.

Would you like more details on the steps?

Here are some related questions:

  1. What happens if we include higher-order terms in the Taylor series?
  2. How does the accuracy of the approximation change if we expand around a different point?
  3. Can Taylor series be used for functions with discontinuities?
  4. What is the geometric interpretation of a Taylor series?
  5. How does the remainder term in the Taylor series affect the accuracy of approximation?

Tip: When approximating a function using Taylor series, more terms generally provide better accuracy, especially near the point of expansion.

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Math Problem Analysis

Mathematical Concepts

Taylor Series Expansion
Derivatives
Polynomial Functions

Formulas

Taylor series expansion: f(x) ≈ f(a) + f'(a)(x - a) + f''(a)/2!(x - a)^2 + f'''(a)/3!(x - a)^3 + ...
First derivative: f'(x) = 25x^4 + 16x^3 + 9x^2 + 4x + 1
Second derivative: f''(x) = 100x^3 + 48x^2 + 18x + 4

Theorems

Taylor Series Theorem

Suitable Grade Level

College or Advanced High School (Grade 12)