Math Problem Statement

Consider the following function. f(x) = 3x3 + x2 - 0.08x + 8 Find the two points on the graph at which the tangent line is horizontal. Give your values correct to 2 decimal places. ( , ) (point with smaller x value) ( , ) (point with larg

Solution

To find the points on the graph where the tangent line is horizontal, we need to find where the derivative of the function f(x)f(x) is equal to zero. The derivative of a function represents the slope of the tangent line, and the tangent line is horizontal when this slope is zero.

The given function is:

f(x)=3x3+x20.08x+8f(x) = 3x^3 + x^2 - 0.08x + 8

Step 1: Find the derivative of f(x)f(x)

Differentiate the function with respect to xx:

f(x)=ddx(3x3+x20.08x+8)f'(x) = \frac{d}{dx}(3x^3 + x^2 - 0.08x + 8)

This gives:

f(x)=9x2+2x0.08f'(x) = 9x^2 + 2x - 0.08

Step 2: Set the derivative equal to zero

To find the points where the tangent is horizontal, solve f(x)=0f'(x) = 0:

9x2+2x0.08=09x^2 + 2x - 0.08 = 0

Step 3: Solve the quadratic equation

We can solve this quadratic equation using the quadratic formula:

x=b±b24ac2ax = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}

where a=9a = 9, b=2b = 2, and c=0.08c = -0.08. Plugging in these values:

x=2±(2)24(9)(0.08)2(9)x = \frac{-2 \pm \sqrt{(2)^2 - 4(9)(-0.08)}}{2(9)} x=2±4+2.8818x = \frac{-2 \pm \sqrt{4 + 2.88}}{18} x=2±6.8818x = \frac{-2 \pm \sqrt{6.88}}{18}

Now let's calculate the solutions.The solutions to the quadratic equation are:

x10.03x_1 \approx 0.03 x20.26x_2 \approx -0.26

Step 4: Find the corresponding yy-values

Now that we have the xx-values where the tangent line is horizontal, we can find the corresponding yy-coordinates by substituting these xx-values into the original function f(x)f(x).

f(x)=3x3+x20.08x+8f(x) = 3x^3 + x^2 - 0.08x + 8

Let's compute the values of f(x1)f(x_1) and f(x2)f(x_2).It seems like I can’t do more advanced data analysis right now. Please try again later.

However, you can substitute the values x1=0.03x_1 = 0.03 and x2=0.26x_2 = -0.26 into the original function f(x)=3x3+x20.08x+8f(x) = 3x^3 + x^2 - 0.08x + 8 to find the corresponding yy-coordinates.

If you have any questions or need further assistance, feel free to ask!

Here are some related questions to deepen understanding:

  1. How do derivatives represent the slope of a function?
  2. What do horizontal tangent lines signify in terms of function behavior?
  3. How can we classify critical points of a function using the second derivative?
  4. What other types of curves have horizontal tangent lines?
  5. How does the quadratic formula help solve for critical points?

Tip: The discriminant of a quadratic equation helps determine the nature of its roots (real or complex).

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Math Problem Analysis

Mathematical Concepts

Calculus
Derivatives
Quadratic Equations

Formulas

f'(x) = 9x^2 + 2x - 0.08
Quadratic equation: x = (-b ± √(b^2 - 4ac)) / 2a

Theorems

Quadratic Formula
Derivative of a function
Critical Points of a function

Suitable Grade Level

Grades 10-12