Math Problem Statement

lim (x→0) (x^2 - 3sin(x)) / x

Solution

The given expression is:

limx0x23sin(x)x\lim_{x \to 0} \frac{x^2 - 3\sin(x)}{x}

Let's solve this limit step by step:

Step 1: Evaluate directly at x=0x = 0

Substitute x=0x = 0 into the function:

023sin(0)0=000=00\frac{0^2 - 3\sin(0)}{0} = \frac{0 - 0}{0} = \frac{0}{0}

This results in an indeterminate form 00\frac{0}{0}, so we need to apply L'Hôpital's Rule or simplify the expression further.

Step 2: Apply L'Hôpital's Rule

L'Hôpital's Rule states that for indeterminate forms like 00\frac{0}{0}, we can differentiate the numerator and the denominator and then take the limit.

  • The derivative of the numerator x23sin(x)x^2 - 3\sin(x) is: ddx(x23sin(x))=2x3cos(x)\frac{d}{dx} (x^2 - 3\sin(x)) = 2x - 3\cos(x)

  • The derivative of the denominator xx is: ddxx=1\frac{d}{dx} x = 1

Now the limit becomes: limx02x3cos(x)1=limx0(2x3cos(x))\lim_{x \to 0} \frac{2x - 3\cos(x)}{1} = \lim_{x \to 0} (2x - 3\cos(x))

Step 3: Evaluate the new limit

Substitute x=0x = 0 into the new expression: 2(0)3cos(0)=03(1)=32(0) - 3\cos(0) = 0 - 3(1) = -3

Final Answer:

The limit is:

3\boxed{-3}

Would you like a detailed explanation on any part of this process?

Here are 5 related questions to expand on this concept:

  1. How does L'Hôpital's Rule work for indeterminate forms other than 00\frac{0}{0}?
  2. Can L'Hôpital's Rule always be applied when faced with indeterminate forms?
  3. What is the significance of the sin(x)\sin(x) and cos(x)\cos(x) behavior near zero?
  4. How would this limit change if there were a higher power of xx in the denominator?
  5. What are some common tricks for evaluating limits without using L'Hôpital's Rule?

Tip: Always check if a limit leads to an indeterminate form before deciding to use L'Hôpital's Rule.

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Math Problem Analysis

Mathematical Concepts

Limits
Indeterminate Forms
L'Hôpital's Rule
Trigonometric Functions

Formulas

L'Hôpital's Rule: lim (x→c) f(x)/g(x) = lim (x→c) f'(x)/g'(x) when lim f(x)/g(x) gives 0/0 or ∞/∞
sin(0) = 0
cos(0) = 1

Theorems

L'Hôpital's Rule

Suitable Grade Level

Grades 11-12 or early college level (calculus)