Math Problem Statement

For f(x) = 1/(6 + x^2), the slope of the graph of y = f(x) is known to be -1/25 at the point with x-coordinate 2. Find the equation of the tangent line at that point.

Solution

We are asked to find the equation of the tangent line to the curve f(x)=16+x2f(x) = \frac{1}{6 + x^2} at the point where x=2x = 2 and the slope of the tangent line is given as 125-\frac{1}{25}.

Steps:

  1. Tangent line equation form: The general equation of the tangent line at a point x=ax = a is: yf(a)=m(xa)y - f(a) = m(x - a) where mm is the slope of the tangent line at x=ax = a.

  2. Given slope: The slope at x=2x = 2 is provided as m=125m = -\frac{1}{25}.

  3. Find f(2)f(2): We need the value of the function at x=2x = 2: f(2)=16+22=16+4=110f(2) = \frac{1}{6 + 2^2} = \frac{1}{6 + 4} = \frac{1}{10}

  4. Substitute values into the tangent line equation: Using x=2x = 2, f(2)=110f(2) = \frac{1}{10}, and m=125m = -\frac{1}{25}, we substitute into the tangent line formula: y110=125(x2)y - \frac{1}{10} = -\frac{1}{25}(x - 2)

  5. Simplify the equation: Distribute the slope on the right-hand side: y110=125x+225y - \frac{1}{10} = -\frac{1}{25}x + \frac{2}{25} Add 110\frac{1}{10} to both sides to solve for yy: y=125x+225+110y = -\frac{1}{25}x + \frac{2}{25} + \frac{1}{10} To combine 225\frac{2}{25} and 110\frac{1}{10}, convert 110\frac{1}{10} to have a denominator of 25: [ \frac{1}{10} = \frac{2.5}{25} = \frac{5}{50}

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Math Problem Analysis

Mathematical Concepts

Calculus
Derivative
Tangent Line

Formulas

Tangent line equation: y - f(a) = m(x - a)

Theorems

Derivative as the slope of the tangent line

Suitable Grade Level

Grades 11-12