Math Problem Statement

Suppose that f(2) = 4 and f'(x) = 3^x. What is the equation of the tangent line to f(x) at x = 2?

Solution

We are given the following:

  • f(2)=4f(2) = 4
  • f(x)=3xf'(x) = 3^x
  • We need to find the equation of the tangent line to f(x)f(x) at x=2x = 2.

Steps to Solve:

  1. Slope of the tangent line: The slope of the tangent line at x=2x = 2 is given by f(2)f'(2), which we can calculate by substituting x=2x = 2 into the derivative f(x)=3xf'(x) = 3^x: f(2)=32=9f'(2) = 3^2 = 9 So, the slope of the tangent line is 99.

  2. Point on the curve: The point at which the tangent line touches the curve is (2,f(2))(2, f(2)). From the problem, we are given f(2)=4f(2) = 4, so the point is (2,4)(2, 4).

  3. Equation of the tangent line: The equation of a line is given by the point-slope form: yy1=m(xx1)y - y_1 = m(x - x_1) where mm is the slope and (x1,y1)(x_1, y_1) is the point on the line. Substituting m=9m = 9 and (x1,y1)=(2,4)(x_1, y_1) = (2, 4): y4=9(x2)y - 4 = 9(x - 2) Simplifying: y4=9x18y - 4 = 9x - 18 y=9x14y = 9x - 14

Final Answer:

The equation of the tangent line to f(x)f(x) at x=2x = 2 is: y=9x14y = 9x - 14

Would you like more details on any step or have any other questions?

Here are 5 related questions to explore:

  1. How would the tangent line change if f(x)f'(x) was a different exponential function?
  2. What is the geometric meaning of the tangent line?
  3. How do you determine the slope of a tangent line for functions with higher powers of xx?
  4. How can the equation of the normal line be derived using the same information?
  5. What role does the derivative play in understanding the behavior of functions?

Tip: Remember, the derivative at a point gives the slope of the tangent line at that point.

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Math Problem Analysis

Mathematical Concepts

Differentiation
Tangent Line
Exponential Functions

Formulas

Point-slope form of a line: y - y1 = m(x - x1)
Derivative of an exponential function: f'(x) = 3^x

Theorems

Derivative as the slope of the tangent line

Suitable Grade Level

Grades 11-12 or Early College