Math Problem Statement

find all x values on the graph of f(x) = x-2cos(x) where the tangent line has slope 1

Solution

To find all xx values where the tangent line to the graph of the function f(x)=x2cos(x)f(x) = x - 2\cos(x) has a slope of 1, we follow these steps:

1. Take the derivative of f(x)f(x)

The derivative of a function gives the slope of the tangent line at any point xx. The derivative of f(x)f(x) is:

f(x)=ddx(x2cos(x))f'(x) = \frac{d}{dx} \left( x - 2\cos(x) \right)

Using basic differentiation rules:

f(x)=1+2sin(x)f'(x) = 1 + 2\sin(x)

2. Set the derivative equal to 1

Since the slope of the tangent line is given as 1, we set f(x)=1f'(x) = 1:

1+2sin(x)=11 + 2\sin(x) = 1

3. Solve for xx

Simplify the equation:

2sin(x)=02\sin(x) = 0

sin(x)=0\sin(x) = 0

Now, solve for xx. The general solutions for sin(x)=0\sin(x) = 0 are:

x=nπwherenZx = n\pi \quad \text{where} \quad n \in \mathbb{Z}

4. Conclusion

The values of xx where the tangent line to the graph of f(x)=x2cos(x)f(x) = x - 2\cos(x) has a slope of 1 are:

x=nπwherenZ (any integer).x = n\pi \quad \text{where} \quad n \in \mathbb{Z} \ (\text{any integer}).

Would you like more details or have any questions on this?

Related questions:

  1. How would the solution change if the slope of the tangent line were different?
  2. What is the significance of nπn\pi in terms of periodicity on the graph?
  3. How do we determine the concavity of f(x)=x2cos(x)f(x) = x - 2\cos(x)?
  4. What does the second derivative tell us about the behavior of f(x)f(x)?
  5. How can you graphically interpret the result x=nπx = n\pi?

Tip:

The sine function sin(x)=0\sin(x) = 0 repeats periodically, which is why the solution is valid for any integer nn. Keep this in mind when solving trigonometric equations.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Calculus
Differentiation
Trigonometry

Formulas

Derivative of f(x) = x - 2cos(x) → f'(x) = 1 + 2sin(x)
Solving sin(x) = 0 → x = nπ where n ∈ ℤ

Theorems

Derivative gives the slope of the tangent line
Periodic property of sine function

Suitable Grade Level

Grades 11-12 / College Calculus 1