Math Problem Statement

Evaluate the following limits: 1. lim (x -> 2) sqrt(5x + 6) / (x - 4) 2. lim (x -> 1) (2x + 3x^2 - 2) / (x - 1) 3. lim (x -> 0) x / (1 - sqrt(1 - x)) 4. lim (x -> 0) (sqrt(x^2 + 1) - sqrt(2)) / x 5. lim (x -> 2) (x^2 - 4) / (sqrt(3x + 2) - 2)

Solution

The image contains several limit problems. Let's transcribe and solve them one by one.

1. limx25x+6x4\lim_{x \to 2} \frac{\sqrt{5x + 6}}{x - 4}

This is an indeterminate form at x=2x = 2, so we can use L'Hôpital's Rule: Differentiate the numerator: ddx5x+6=525x+6\text{Differentiate the numerator: } \frac{d}{dx} \sqrt{5x + 6} = \frac{5}{2\sqrt{5x + 6}} Differentiate the denominator: ddx(x4)=1\text{Differentiate the denominator: } \frac{d}{dx}(x - 4) = 1 Using L'Hôpital's Rule: limx2525x+61=525(2)+6=5210+6=5216=52×4=58\lim_{x \to 2} \frac{\frac{5}{2\sqrt{5x + 6}}}{1} = \frac{5}{2\sqrt{5(2) + 6}} = \frac{5}{2\sqrt{10 + 6}} = \frac{5}{2\sqrt{16}} = \frac{5}{2 \times 4} = \frac{5}{8} So, the solution is: 58\boxed{\frac{5}{8}}

2. limx1(2x+3x2)2x1\lim_{x \to 1} \frac{(2x + 3x^2) - 2}{x - 1}

At x=1x = 1, we have a 00\frac{0}{0} indeterminate form. Let's simplify by factoring or applying L'Hôpital's Rule. First, rewrite and differentiate:

Differentiate the numerator: ddx(2x+3x22)=2+6x\frac{d}{dx} (2x + 3x^2 - 2) = 2 + 6x Denominator derivative: ddx(x1)=1\frac{d}{dx}(x - 1) = 1 Now apply L'Hôpital's Rule: limx12+6x1=2+6(1)=2+6=8\lim_{x \to 1} \frac{2 + 6x}{1} = 2 + 6(1) = 2 + 6 = 8 Thus, the limit is: 8\boxed{8}

3. limx0x11x\lim_{x \to 0} \frac{x}{1 - \sqrt{1 - x}}

At x=0x = 0, we have the indeterminate form 00\frac{0}{0}, so we'll apply L'Hôpital's Rule again.

Differentiate the numerator: ddx(x)=1\frac{d}{dx} (x) = 1 Differentiate the denominator: ddx(11x)=121x\frac{d}{dx} (1 - \sqrt{1 - x}) = \frac{1}{2\sqrt{1 - x}} Now apply L'Hôpital's Rule: limx01121x=210=2\lim_{x \to 0} \frac{1}{\frac{1}{2\sqrt{1 - x}}} = 2\sqrt{1 - 0} = 2 Thus, the limit is: 2\boxed{2}

4. limx0x2+12x\lim_{x \to 0} \frac{\sqrt{x^2 + 1} - \sqrt{2}}{x}

At x=0x = 0, we have the indeterminate form 00\frac{0}{0}, so again we apply L'Hôpital's Rule.

Differentiate the numerator: ddx(x2+12)=xx2+1\frac{d}{dx} \left( \sqrt{x^2 + 1} - \sqrt{2} \right) = \frac{x}{\sqrt{x^2 + 1}} Denominator derivative: ddx(x)=1\frac{d}{dx}(x) = 1 Now apply L'Hôpital's Rule: limx0xx2+11=002+1=0\lim_{x \to 0} \frac{\frac{x}{\sqrt{x^2 + 1}}}{1} = \frac{0}{\sqrt{0^2 + 1}} = 0 Thus, the limit is: 0\boxed{0}

5. limx2x243x+22\lim_{x \to 2} \frac{x^2 - 4}{\sqrt{3x + 2} - 2}

At x=2x = 2, we have a 00\frac{0}{0} indeterminate form. Let's multiply by the conjugate to simplify.

Multiply numerator and denominator by 3x+2+2\sqrt{3x + 2} + 2: x243x+223x+2+23x+2+2=(x2)(x+2)(3x+2)222\frac{x^2 - 4}{\sqrt{3x + 2} - 2} \cdot \frac{\sqrt{3x + 2} + 2}{\sqrt{3x + 2} + 2} = \frac{(x - 2)(x + 2)}{(\sqrt{3x + 2})^2 - 2^2} Simplifying the denominator: (3x+2)222=(3x+2)4=3x2(\sqrt{3x + 2})^2 - 2^2 = (3x + 2) - 4 = 3x - 2 Thus, the expression becomes: limx2(x2)(x+2)3x2\lim_{x \to 2} \frac{(x - 2)(x + 2)}{3x - 2} At x=2x = 2, the denominator does not go to 0, so we can directly substitute: (22)(2+2)3(2)2=062=0\frac{(2 - 2)(2 + 2)}{3(2) - 2} = \frac{0}{6 - 2} = 0 Thus, the limit is: 0\boxed{0}


Would you like a detailed explanation for any of the steps? Here are five related problems to further explore these concepts:

  1. Find limx3x29x3\lim_{x \to 3} \frac{x^2 - 9}{x - 3}.
  2. Compute limx1x1x1\lim_{x \to 1} \frac{\sqrt{x} - 1}{x - 1}.
  3. Evaluate limx0xex1\lim_{x \to 0} \frac{x}{e^x - 1}.
  4. Solve limx01cosxx2\lim_{x \to 0} \frac{1 - \cos x}{x^2}.
  5. Determine limx1x31x1\lim_{x \to 1} \frac{x^3 - 1}{x - 1}.

Tip: When you encounter indeterminate forms like 00\frac{0}{0}, try applying L'Hôpital's Rule or algebraic simplifications such as factoring or multiplying by conjugates.

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Math Problem Analysis

Mathematical Concepts

Limits
Indeterminate forms
L'Hôpital's Rule
Algebraic manipulation

Formulas

L'Hôpital's Rule: lim (x -> a) f(x) / g(x) = lim (x -> a) f'(x) / g'(x), if the form is indeterminate
Square root simplifications and conjugates

Theorems

L'Hôpital's Rule

Suitable Grade Level

Grade 12 or College Level Calculus