Math Problem Statement

Write the equation of a tangent line to the function evaluated at the given point. f(x) = 2 ln(x) at x = 3. What is the equation of the tangent line in y = mx + b form?

Solution

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"3. Write the equation of a tangent line to the function evaluated at the given point. f(x) = 2 ln(x) at x = 3. What is the equation of the tangent line in y = mx + b form?"

Solution:

To find the equation of the tangent line, we need to follow these steps:

  1. Find the derivative of the function f(x)=2ln(x)f(x) = 2 \ln(x) to determine the slope of the tangent line.

    The derivative f(x)f'(x) represents the slope of the tangent line at any point xx.

    f(x)=ddx[2ln(x)]=2xf'(x) = \frac{d}{dx} [2 \ln(x)] = \frac{2}{x}

  2. Evaluate the derivative at x=3x = 3 to find the slope of the tangent line at that specific point.

    f(3)=23f'(3) = \frac{2}{3}

    So, the slope mm of the tangent line at x=3x = 3 is 23\frac{2}{3}.

  3. Find the function value at x=3x = 3 to determine the point on the curve where the tangent line touches.

    f(3)=2ln(3)f(3) = 2 \ln(3)

    Therefore, the point is (3,2ln(3))(3, 2\ln(3)).

  4. Use the point-slope form of a line to find the equation of the tangent line. The point-slope form is given by:

    yy1=m(xx1)y - y_1 = m(x - x_1)

    Substituting m=23m = \frac{2}{3}, x1=3x_1 = 3, and y1=2ln(3)y_1 = 2 \ln(3):

    y2ln(3)=23(x3)y - 2 \ln(3) = \frac{2}{3}(x - 3)

  5. Solve for yy to get the equation in the form y=mx+by = mx + b:

    y=23x+2ln(3)2y = \frac{2}{3}x + 2 \ln(3) - 2

Thus, the equation of the tangent line in y=mx+by = mx + b form is:

y=23x+2ln(3)2y = \frac{2}{3}x + 2 \ln(3) - 2


Do you want details or have any questions?

Here are five related questions to consider:

  1. How do you find the derivative of more complex logarithmic functions?
  2. What is the significance of the point-slope form of a line?
  3. How would the tangent line change if the point were different, say at x=1x = 1?
  4. What are some real-world applications of finding the tangent line to a curve?
  5. Can you explain why the tangent line is an approximation of the function near the point of tangency?

Tip: Understanding how to find the derivative is key to solving problems involving the slope of a tangent line. Practice differentiating various types of functions to improve your skills.

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Math Problem Analysis

Mathematical Concepts

Calculus
Differentiation
Logarithmic Functions
Tangent Line

Formulas

Derivative of logarithmic function: d/dx [ln(x)] = 1/x
Point-slope form of a line: y - y1 = m(x - x1)

Theorems

Derivative rules for logarithmic functions
Equation of a tangent line

Suitable Grade Level

Grades 11-12