32. Let \( f \) be the function given by \[ f(x) = 3x^2 - 4x + 2. \] The tangent line to the graph of \( f \) at \( x = 1 \) is used to approximate values of \( f(x) \). Which of the following is the smallest value of \( x \) for which the error resulting from this tangent line approximation is more than 0.5?

Hint for your calculator use: Create a table to compare values of two functions. (calculator)






Answer is: option3

1.5

Solution:

We are given the function:

\[ f(x) = 3x^2 - 4x + 2 \] Find \( f(1) \) \[ f(1) = 3(1)^2 - 4(1) + 2 = 3 - 4 + 2 = 1 \] Find \( f'(x) \)

Differentiate \( f(x) \):

\[ f'(x) = \frac{d}{dx} (3x^2 - 4x + 2) = 6x - 4 \]

Now, evaluate \( f'(1) \):

\[ f'(1) = 6(1) - 4 = 6 - 4 = 2 \] Equation of the Tangent Line at \( x = 1 \)

The tangent line follows the point-slope formula:

\[ y - f(1) = f'(1)(x - 1) \]

Substituting values:

\[ y - 1 = 2(x - 1) \] \[ y = 2x - 2 + 1 \] \[ y = 2x - 1 \]

So, the tangent line equation is:

\[ L(x) = 2x - 1 \] Finding the Smallest \( x \) for \( |f(x) - L(x)| > 0.5 \)

From the computed table, we observe that the error \( |f(x) - L(x)| \) exceeds 0.5 for the first time at \( x = 1.5 \).

x f(x) L(x) |f(x) - L(x)|
1.3 1.87 1.6 0.27
1.4 2.28 1.8 0.48
1.5 2.75 2.0 0.75
1.6 3.28 2.2 1.08
1.7 3.87 2.4 1.47
Final Answer

Thus, the smallest value of \( x \) for which the error is more than 0.5 is: 1.5

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