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The tangent line approximation

The line y = f(a) + f'(a)(x - a) as a local stand-in for f, the idea of local linearity, and how concavity says whether that estimate runs high or low.

Active Calculus, The tangent line approximation

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3 exercises

Exercise 8

A potato is placed in an oven, and the potato's temperature FF (in degrees Fahrenheit) at various points in time is taken and recorded in the following table. Time tt is measured in minutes.

  1. Use a central difference to estimate F′(30)F'(30). Use this estimate as needed in subsequent questions.

  2. Find the local linearization y=L(t)y = L(t) to the function y=F(t)y = F(t) at the point where a=30a = 30.

  3. Determine an estimate for F(33)F(33) by employing the local…

2.5

Exercise 9

An object moving along a straight line path has a differentiable position function y=s(t)y = s(t); s(t)s(t) measures the object's position relative to the origin at time tt. It is known that at time t=9t = 9 seconds, the object's position is s(9)=4s(9) = 4 feet (i.e., 4 feet to the right of the origin). Furthermore, the object's instantaneous velocity at t=9t = 9 is −1.2-1.2 feet per second, and its acceleration at the same instant is 0.080.08 feet per secon…

2.5

Exercise 10

For a certain function ff, its derivative is known to be f′(x)=(x−1)e−x2f'(x) = (x-1)e^{-x^2}. Note that you do not know a formula for y=f(x)y = f(x).

  1. At what xx-value(s) is f′(x)=0f'(x) = 0? Justify your answer algebraically, but include a graph of f′f' to support your conclusion.

  2. Reasoning graphically, for what intervals of xx-values is f′′(x)>0f''(x) \gt 0? What does this tell you about the behavior of the original function ff? Explain.

  3. Assuming that f(2)=−3f(2) = -3, estimate the value of f(1.88)f(1.88) by find…

2.5

Adapted from Active Calculus © 2012–2025 Matthew Boelkins. Licensed under CC BY-SA 4.0. Source: Active Calculus. Imported at revision dc86ba3.