Math Problem Statement

lim x tends to zero [e^x - ( 1 + x + (x^2/2))]

Solution

We are tasked with evaluating the limit:

limx0(ex(1+x+x22))\lim_{x \to 0} \left( e^x - \left(1 + x + \frac{x^2}{2} \right) \right)

Step-by-Step Solution:

  1. Recall the Taylor expansion of exe^x around x=0x = 0:

    ex=1+x+x22+x36+x424+e^x = 1 + x + \frac{x^2}{2} + \frac{x^3}{6} + \frac{x^4}{24} + \cdots

  2. Subtract the polynomial 1+x+x221 + x + \frac{x^2}{2} from exe^x:

    ex(1+x+x22)=(1+x+x22+x36+)(1+x+x22)e^x - \left( 1 + x + \frac{x^2}{2} \right) = \left( 1 + x + \frac{x^2}{2} + \frac{x^3}{6} + \cdots \right) - \left( 1 + x + \frac{x^2}{2} \right)

    Simplifying this expression:

    ex(1+x+x22)=x36+x424+e^x - \left( 1 + x + \frac{x^2}{2} \right) = \frac{x^3}{6} + \frac{x^4}{24} + \cdots

  3. Take the limit as x0x \to 0:

    Since each term in the series starting from x36\frac{x^3}{6} involves powers of xx higher than 2, all these terms vanish as x0x \to 0.

    limx0(x36+x424+)=0\lim_{x \to 0} \left( \frac{x^3}{6} + \frac{x^4}{24} + \cdots \right) = 0

Thus, the limit is:

0\boxed{0}

Let me know if you need further details or clarifications!

Related questions:

  1. What is the Taylor series of sin(x)\sin(x) around x=0x = 0?
  2. How can we apply L'Hopital's rule to limits involving indeterminate forms?
  3. What is the general form of a Taylor series?
  4. How do we expand ln(1+x)\ln(1+x) around x=0x = 0?
  5. Can you provide an example of a limit using a different function, such as cos(x)\cos(x)?

Tip: Taylor expansions are useful for approximating functions near a specific point, especially when dealing with limits!

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Math Problem Analysis

Mathematical Concepts

Limits
Taylor Series
Exponential Functions

Formulas

Taylor expansion of e^x around x = 0: e^x = 1 + x + (x^2/2) + (x^3/6) + ...
Limit of higher order terms: lim_{x → 0} (x^n) = 0 for n > 2

Theorems

Taylor's Theorem
Properties of Exponential Functions

Suitable Grade Level

Grades 11-12 or introductory college calculus