 # Homework Homework Assignment #1 Review Section 2.1/Read Section 2.2

## Presentation on theme: "Homework Homework Assignment #1 Review Section 2.1/Read Section 2.2"— Presentation transcript:

Homework Homework Assignment #1 Review Section 2.1/Read Section 2.2
Page 66, Exercises: 1 – 9 (Odd), 13 – 29 (EOO) Rogawski Calculus Copyright © 2008 W. H. Freeman and Company

Homework, Page 66 1. A ball is dropped from a state of rest at t = 0. The distance traveled after t sec is s(t) = 16t2. (a) How far does the ball travel during the time interval [2, 2.5]? (b) Compute the average velocity over [2, 2.5]. Rogawski Calculus Copyright © 2008 W. H. Freeman and Company

Homework, Page 66 1. (c) Compute the average velocity over the time intervals [2, 2.01], [2, 2.005], [2, ]. Use this to estimate the object’s instantaneous velocity at t = 2. Rogawski Calculus Copyright © 2008 W. H. Freeman and Company

Homework, Page 66 3. Let Estimate the instantaneous ROC of v with respect to T when T = 300. Rogawski Calculus Copyright © 2008 W. H. Freeman and Company

Homework, Page 66 A stone is tossed in the air from ground level with an initial velocity of 15 m/s. Its height at time t is h(t) = 15t – 4.9t2 m. 5. Compute the stones average velocity over the time interval [0.5, 2.5] and indicate corresponding the corresponding secant line on a sketch of the graph of h(t). Rogawski Calculus Copyright © 2008 W. H. Freeman and Company

Homework, Page 66 7. With an initial deposit of \$100, the balance in a bank account after t years is f(t) = 100(1.08)t dollars. (a) What are the units of the ROC of f(t)? The units of the ROC of f (t) are dollars per year. (b) Find the average ROC over [0, 0.5] and [0, 1]. Rogawski Calculus Copyright © 2008 W. H. Freeman and Company

Homework, Page 66 (c) Estimate the instantaneous ROC at t = 0.5 by computing the average ROC over intervals to the right and left of t = 0.5. Rogawski Calculus Copyright © 2008 W. H. Freeman and Company

Homework, Page 66 Estimate the instantaneous ROC at the indicated point. Rogawski Calculus Copyright © 2008 W. H. Freeman and Company

Homework, Page 66 Estimate the instantaneous ROC at the indicated point. Rogawski Calculus Copyright © 2008 W. H. Freeman and Company

Homework, Page 66 17. The atmospheric temperature T (in ºF) above a certain point is T = 59 – h, where h is the altitude in feet (h ≤ 37,000 ft). What are the average and instantaneous ROC of T with respect to h? Why are they the same? Sketch the graph of T. The secant line and the graph of T are the same line, so the average and instantaneous ROC are both equal to – Rogawski Calculus Copyright © 2008 W. H. Freeman and Company

Homework, Page 66 21. Assume that the period T (in sec) of a pendulum is where L is the length (in m). (a) What are the units for ROC of the T with respect to L? Explain what this rate measures. The units of the ROC of T are sec/m, giving the rate at which the period changes when length changes. (b) What quantities are represented by the slopes of lines A and B in Figure 10? Lines A and B represent instantaneous and average ROC. Rogawski Calculus Copyright © 2008 W. H. Freeman and Company

Homework, Page 66 25. The fraction of a city’s population infected by a flu virus is plotted as a function of time in weeks in Figure 14. (a) Which quantities are represented by the slopes of lines A and B? Estimate these slopes. The slope of line A represents the average ROC over weeks 4 through 6. The slope of line B represents the instantaneous ROC in week 6. The slopes appear to be about , respectively. Rogawski Calculus Copyright © 2008 W. H. Freeman and Company

Homework, Page 66 25. (b) Is the flu spreading most rapidly at t = 1, 2, or 3? The flu is spreading most rapidly at t = 3 , as the slope is greatest at that point. (c) Is the flu spreading most rapidly t = 4, 5, or 6? The flu is spreading most rapidly at t = 4, as the slope is greatest at that point. Rogawski Calculus Copyright © 2008 W. H. Freeman and Company

Homework, Page 66 29. Sketch the graph of f (x) = x (1 – x) over [0, 1]. Refer to the graph and find: (a) The average ROC over [0, 1]. average ROC = 0 (b) The instantaneous ROC at x = 0.5. instantaneous ROC = 0 (c) The values of x for which ROC is positive. ROC is positive for x < 0.5. Rogawski Calculus Copyright © 2008 W. H. Freeman and Company

Section 2.2: Limits: A Numerical and Graphical Approach
Jon Rogawski Calculus, ET First Edition Chapter 2: Limits Section 2.2: Limits: A Numerical and Graphical Approach Rogawski Calculus Copyright © 2008 W. H. Freeman and Company

Section 2.2 Notes and Examples
In previous courses, we have considered limits when looking at the end behavior of a function. For instance, the function y = 2 + e–x asymptotically approaches y = 2 as x approaches infinity. Mathematically, we could write this as: Similarly: In this section we will look at the behavior of the values of f (x) as x approaches some number c, whether or not f (c) is defined. Rogawski Calculus Copyright © 2008 W. H. Freeman and Company

Section 2.2 Notes and Examples
Consider the function as x approaches 0. The function is not defined at x = 0, but it is defined for values of x very close to 0. By examining these values in the table below, we see that f (x) approaches 1 as x approaches 0 or Rogawski Calculus Copyright © 2008 W. H. Freeman and Company

Example, Page 76 Fill in the table and guess the value of the limit. θ
±0.002 ±0.0001 ± ± f (+θ) f (–θ) Rogawski Calculus Copyright © 2008 W. H. Freeman and Company

Section 2.2 Notes and Examples
Recalling that the distance between points a and b is |b – a|, If the values of f (x) do not converge to any finite value as x approaches c, we say that Rogawski Calculus Copyright © 2008 W. H. Freeman and Company

Example, Page 76 Verify each limit using the limit definition.

Section 2.2 Notes and Examples
Theorem 1 states two simple, yet important concepts, which are illustrated in the graph below. The value of constant k is independent of the value of x, as is the value of c. Rogawski Calculus Copyright © 2008 W. H. Freeman and Company

Graphical Investigation
Use the graphing calculator to graph the function in the vicinity of the value of x in question. If the graph appears to approach the same point from either side of the value in question, then we may say that the limit exists, and the limit may frequently be estimated directly from the graph. Rogawski Calculus Copyright © 2008 W. H. Freeman and Company

Example, Page 76 Verify each limit using the limit definition.

Numerical Investigation
Section 2.2 Notes and Examples Numerical Investigation Construct a table of values of f (x) for x close to, but less than c. Construct a second table of values of f (x) for x close to, but greater than c. If both tables indicate convergence to the same number L, we take L to be an estimate for the limit. Rogawski Calculus Copyright © 2008 W. H. Freeman and Company

Section 2.2 Notes and Examples
The graph and table below illustrate graphical and numerical investigation of: Rogawski Calculus Copyright © 2008 W. H. Freeman and Company

Section 2.2 Notes and Examples
The graph and table below illustrate graphical and numerical investigation of: Rogawski Calculus Copyright © 2008 W. H. Freeman and Company

Section 2.2 Notes and Examples
The graph and table below illustrate graphical and numerical investigation of: Rogawski Calculus Copyright © 2008 W. H. Freeman and Company

Section 2.2 Notes and Examples
The graph below doesn’t really answer the question of the existence of a limit, but the table shows that it does not exist as the values of sin (1/x) have opposite signs when the same distance from zero in the positive and negative directions is considered. Thus: Rogawski Calculus Copyright © 2008 W. H. Freeman and Company

Section 2.2 Notes and Examples

Section 2.2 Notes and Examples
Figure 7 shows the graph of a piecewise function. The limits as x approaches 0 and 2 do not exist, but the limit as x approaches 4 appears to exist, as the graph on both sides of x = 4 seems to converge on the same value of y. The following one-sided limits also appear to exist: but DNE as the values of f (x) continue to oscillate between ±1 as x gets ever closer to 0. Rogawski Calculus Copyright © 2008 W. H. Freeman and Company

Definition The limit of a function at a given point exists if, and only if, the one-sided limits at the point are equal. Mathematically, we state: Rogawski Calculus Copyright © 2008 W. H. Freeman and Company

Example, Page 76 38. Determine the one-sided limits at c = 1, 2, 4 of the function g(t) shown in the figure and state whether the limit exists at these points. Rogawski Calculus Copyright © 2008 W. H. Freeman and Company

Section 2.2 Notes and Examples
Graphs (A) and (B) in Figure 8 illustrate functions with infinite discontinuities. Graph (C) illustrates a function with the interesting property: Rogawski Calculus Copyright © 2008 W. H. Freeman and Company

Example, Page 76 Draw the graph of a function with the given limits.