Math Problem Statement

Using symbolic notation

Solution

The expression in the image is:

limx03x21ex\lim_{x \to 0} \frac{3x^2}{1 - e^x}

To solve this limit, we can start by evaluating the limit directly:

  1. Substitute x=0x = 0 into the expression:

    3(0)21e0=011=00\frac{3(0)^2}{1 - e^0} = \frac{0}{1 - 1} = \frac{0}{0}

    The result is an indeterminate form 00\frac{0}{0}, so we need to apply L'Hôpital's rule.

  2. Apply L'Hôpital's rule:

    L'Hôpital's rule states that if the limit results in an indeterminate form like 00\frac{0}{0}, we can differentiate the numerator and the denominator separately and then take the limit:

    • Differentiate the numerator 3x23x^2 with respect to xx: ddx(3x2)=6x\frac{d}{dx} (3x^2) = 6x

    • Differentiate the denominator 1ex1 - e^x with respect to xx: ddx(1ex)=ex\frac{d}{dx} (1 - e^x) = -e^x

    Now, the limit becomes: limx06xex\lim_{x \to 0} \frac{6x}{-e^x}

  3. Evaluate the new limit:

    Substitute x=0x = 0 into the new expression: 6(0)e0=01=0\frac{6(0)}{-e^0} = \frac{0}{-1} = 0

So, the limit is:

limx03x21ex=0\lim_{x \to 0} \frac{3x^2}{1 - e^x} = 0

Would you like any further details or explanations? Here are some additional questions to consider:

  1. How is L'Hôpital's rule applied when the limit results in \frac{\infty}{\infty}?
  2. What are some alternative methods to solve limits without using L'Hôpital's rule?
  3. How do you differentiate exe^x and why is it the same as exe^x?
  4. What happens to the limit if the numerator had a higher power of xx?
  5. How can you verify the result using a series expansion for exe^x?

Tip: L'Hôpital's rule is useful for handling limits that result in indeterminate forms, but it’s important to remember that the rule only applies when you have these specific forms like 00\frac{0}{0} or \frac{\infty}{\infty}.