Math Problem Statement

Find an equation of the tangent line to the curve at the given point: f(x) = -2x²+1 at (2, -7)

Solution

To find the equation of the tangent line to the curve f(x)=2x2+1f(x) = -2x^2 + 1 at the point (2,7)(2, -7), we need to follow these steps:

  1. Find the derivative of f(x)f(x): This represents the slope of the tangent line at any point on the curve.
  2. Evaluate the derivative at the given point: This gives the slope of the tangent line at x=2x = 2.
  3. Use the point-slope form of the equation of a line: With the slope and a point on the tangent line, we can find the equation.

Step 1: Find the Derivative

The function given is: f(x)=2x2+1f(x) = -2x^2 + 1

The derivative f(x)f'(x) is found using the power rule: f(x)=ddx(2x2+1)=4xf'(x) = \frac{d}{dx}(-2x^2 + 1) = -4x

Step 2: Evaluate the Derivative at x=2x = 2

Now, plug x=2x = 2 into the derivative to find the slope of the tangent line at this point: f(2)=4(2)=8f'(2) = -4(2) = -8

The slope of the tangent line at x=2x = 2 is 8-8.

Step 3: Use the Point-Slope Form

The point-slope form of a line equation is: yy1=m(xx1)y - y_1 = m(x - x_1)

Here, m=8m = -8, x1=2x_1 = 2, and y1=7y_1 = -7. Plugging in these values gives: y(7)=8(x2)y - (-7) = -8(x - 2)

Simplify the equation: y+7=8x+16y + 7 = -8x + 16

Subtract 7 from both sides: y=8x+9y = -8x + 9

Conclusion

The equation of the tangent line to the curve f(x)=2x2+1f(x) = -2x^2 + 1 at the point (2,7)(2, -7) is: y=8x+9\boxed{y = -8x + 9}

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

Here are some related questions you might find useful:

  1. How do you find the derivative of a polynomial function?
  2. What is the power rule in calculus?
  3. How do you apply the point-slope form to find the equation of a line?
  4. What is the significance of the slope of the tangent line at a point on a curve?
  5. How do you verify that a point lies on the tangent line to a curve?

Tip: Remember that the slope of the tangent line represents the instantaneous rate of change of the function at a specific point.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Calculus
Derivatives
Tangent Lines

Formulas

Point-slope form of a line equation

Theorems

-

Suitable Grade Level

Grades 11-12