Math Problem Statement

The graph of f', the derivative of a function f, is shown above. The points (2, 6) and (4, 18) are on the graph of f. Which of the following is an equation of the line tangent to the graph of f at x = 2?

Solution

To solve this problem, we are looking for the equation of the line tangent to the graph of ff at x=2x = 2, using the graph of ff', which represents the derivative of ff.

Here’s the process step-by-step:

1. Identify the slope of the tangent line at x=2x = 2

The slope of the tangent line to the graph of ff at any point is given by the value of f(x)f'(x). We are asked to find the slope at x=2x = 2.

From the graph of ff', at x=2x = 2, the value of f(2)=5f'(2) = 5 (from the height of the graph at x=2x = 2).

Thus, the slope mm of the tangent line at x=2x = 2 is: m=f(2)=5m = f'(2) = 5

2. Use the point-slope form of the tangent line

We are given the point (2,6)(2, 6) on the graph of ff. The equation of a line can be written in 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=5m = 5 and the point (2,6)(2, 6), we get: y6=5(x2)y - 6 = 5(x - 2) Simplifying: y6=5x10y - 6 = 5x - 10 y=5x4y = 5x - 4

Thus, the equation of the tangent line is y=5x4y = 5x - 4.

3. Conclusion

The correct answer is B y=5x4y = 5x - 4.


Would you like a deeper explanation, or do you have any follow-up questions?

Here are 5 related questions to further explore the topic:

  1. How is the derivative related to the slope of the tangent line?
  2. Why do we use the point-slope form for finding the tangent line?
  3. What is the significance of ff' being positive, negative, or zero at a point?
  4. How do you find the equation of a tangent line if the derivative is given as a function, not a graph?
  5. Can the tangent line intersect the graph of the function at multiple points?

Tip: Always double-check the values from the graph when calculating the slope and ensure you are reading the derivative correctly for precise results.

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Math Problem Analysis

Mathematical Concepts

Calculus
Derivatives
Tangent Lines

Formulas

Point-slope form: y - y₁ = m(x - x₁)

Theorems

Derivative as the slope of the tangent line

Suitable Grade Level

Grades 11-12