Math Problem Statement

Let [f] be a differentiable function with [f(2)=-3] and [f'(2)=-4]. What is the value of the approximation of [f(1.9)] using the function's local linear approximation at [x=2]? Choose 1 answer: Choose 1 answer: (Choice A)
[-2.9] A [-2.9] (Choice B)
[-2.8] B [-2.8] (Choice C)
[-2.7] C [-2.7] (Choice D)
[-2.6] D [-2.6]

Solution

To approximate f(1.9)f(1.9) using the function's local linear approximation at x=2x = 2, we use the formula for the linear approximation:

L(x)=f(a)+f(a)(xa)L(x) = f(a) + f'(a)(x - a)

where:

  • a=2a = 2
  • f(2)=3f(2) = -3
  • f(2)=4f'(2) = -4

We want to find L(1.9)L(1.9). Plugging in the values:

L(1.9)=f(2)+f(2)(1.92)L(1.9) = f(2) + f'(2)(1.9 - 2)

Now substitute the given values:

L(1.9)=3+(4)(1.92)L(1.9) = -3 + (-4)(1.9 - 2)

Calculate the difference 1.921.9 - 2:

1.92=0.11.9 - 2 = -0.1

Then multiply by f(2)=4f'(2) = -4:

4×(0.1)=0.4-4 \times (-0.1) = 0.4

Now, add this result to f(2)=3f(2) = -3:

L(1.9)=3+0.4=2.6L(1.9) = -3 + 0.4 = -2.6

Thus, the value of the approximation of f(1.9)f(1.9) is:

2.6\boxed{-2.6}

The correct choice is:

(Choice D) 2.6-2.6

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

Here are 5 related questions that might help further your understanding:

  1. What is the significance of using a linear approximation for estimating function values?
  2. How would you use the same method to approximate f(2.1)f(2.1)?
  3. What does the derivative f(2)=4f'(2) = -4 tell us about the function f(x)f(x) at x=2x = 2?
  4. How would the linear approximation change if f(2)f'(2) were positive instead of negative?
  5. What is the error involved in using a linear approximation versus using the actual function?

Tip: When using linear approximations, remember that they are more accurate when xx is close to the point aa where the function is being approximated.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Differentiation
Linear approximation

Formulas

Linear approximation formula L(x) = f(a) + f'(a)(x - a)

Theorems

-

Suitable Grade Level

Advanced High School