Math Problem Statement

laske tehtävä

lim_{x \to 5} \frac{\sqrt{7x+5} - \sqrt{3x+25}}{3(x-5)}

Solution

You've provided a limit problem involving a square root expression and a linear expression, specifically:

limx57x+53x+253(x5)\lim_{x \to 5} \frac{\sqrt{7x+5} - \sqrt{3x+25}}{3(x-5)}

To solve this limit, we observe that directly substituting x=5x = 5 into the expression results in an indeterminate form 00\frac{0}{0}. To resolve this, we can apply L'Hôpital's Rule, which states that for functions f(x)f(x) and g(x)g(x) that are differentiable near aa and for which limxaf(x)=limxag(x)=0\lim_{x \to a} f(x) = \lim_{x \to a} g(x) = 0 or ±\pm \infty, the limit of f(x)g(x)\frac{f(x)}{g(x)} as xx approaches aa can be computed as limxaf(x)g(x)\lim_{x \to a} \frac{f'(x)}{g'(x)} if this limit exists.

Let's calculate this using differentiation.

I'll first compute the derivatives of the numerator and the denominator, and then re-evaluate the limit.

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Math Problem Analysis

Mathematical Concepts

Limits
Square Roots
Indeterminate Forms

Formulas

L'Hôpital's Rule
Derivative of square root function: d/dx(√u) = 1/(2√u) * du/dx

Theorems

L'Hôpital's Rule

Suitable Grade Level

College Calculus