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1. –/2 points scalcet7 2.2.002.nvaMy Notes Explain what it means to say that lim

ID: 2889842 • Letter: 1

Question

1.–/2 pointsscalcet7 2.2.002.nvaMy Notes

Explain what it means to say that

lim x 9f(x) = 6  and  lim x 9+f(x) = 3.

As x approaches 9, f(x) approaches 3, but f(9) = 6.

As x approaches 9 from the right, f(x) approaches 6. As x approaches 9 from the left, f(x) approaches 3.

    

As x approaches 9 from the left, f(x) approaches 6. As x approaches 9 from the right, f(x) approaches 3.

As x approaches 9, f(x) approaches 6, but f(9) = 3.


In this situation is it possible that

lim x 9 f(x)

exists? Explain.

Yes, f(x) could have a hole at (9, 6) and be defined such that f(9) = 3.

Yes, f(x) could have a hole at (9, 3) and be defined such that f(9) = 6.

    

Yes, if f(x) has a vertical asymptote at x = 9, it can be defined such that lim x9f(x) = 6, lim x9+f(x) = 3, and lim x9 f(x) exists.

No, lim x9 f(x) cannot exist if lim x9f(x) lim x9+f(x).

2.–/2 pointsscalcet7 2.2.ae.007.nvaMy Notes

EXAMPLE 7 The graph of a function g is shown in the figure. Use it to state the values (if they exist) of the following:

(a)  lim x 2g(x)

(b)  lim x 2+g(x)

(c)  lim x 2 g(x)

(d)  lim x 5g(x)

(e)  lim x 5+g(x)

(f)  lim x 5 g(x).

SOLUTION From the graph we see that the values of g(x) approach  as x approaches 2 from the left, but they approach  as x approaches 2 from the right. Therefore

(a) lim x 2g(x) =      and    (b) lim x 2+g(x) =  .

(c) Since the left and right limits are different, we conclude that the limit as x approaches 2 of g(x) does not exist.

The graph also shows that

(d) lim x 5g(x) =      and    (e) lim x 5+g(x) =  .

(f) This time, the left and right limits are the same and so, by this theorem, we have

lim x 5 g(x) =

Despite this fact, notice that g(5) 4.

3.–/2 pointsscalcet7 2.2.004.nvaMy Notes

Use the given graph of f to state the value of each quantity, if it exists. (If an answer does not exist, enter DNE.)

(a)    

lim x 2f(x)




(b)    

lim x 2+f(x)




(c)    

lim x 2 f(x)




(d)    

f(2)




(e)    

lim x 4 f(x)




(f)    

f(4)

4.–/2 pointsscalcet7 2.2.006.nvaMy Notes

For the function h whose graph is given, state the value of each quantity, if it exists. (If an answer does not exist, enter DNE.)

(a)    

lim x 3h(x)




(b)    

lim x 3+h(x)




(c)    

lim x 3 h(x)




(d)    

h(3)




(e)    

lim x 0h(x)




(f)    

lim x 0+h(x)




(g)    

lim x 0 h(x)




(h)    

h(0)




(i)    

lim x 2 h(x)




(j)    

h(2)




(k)    

lim x 5+h(x)




(l)    

lim x 5h(x)


5.–/2 pointsscalcet7 2.2.007.nvaMy Notes

For the function g whose graph is given, state the value of each quantity, if it exists. (If an answer does not exist, enter DNE.)

(a)    

lim t 0g(t)




(b)    

lim t 0+g(t)




(c)    

lim t 0 g(t)




(d)    

lim t 2g(t)




(e)    

lim t 2+g(t)




(f)    

lim t 2 g(t)




(g)    

g(2)




(h)    

lim t 4 g(t)

6.–/2 pointsscalcet7 2.2.008.nvaMy Notes

For the function R whose graph is shown, state the following. (If an answer does not exist, enter DNE.)

(a)    

lim x 2 R(x)



(b)    

lim x 5 R(x)



(c)    

lim x 3R(x)



(d)    

lim x 3+R(x)



(e) The equations of the vertical asymptotes.

7.–/2 pointsscalcet7 2.2.010.mi.nvaMy Notes

A patient receives a 150-mg injection of a drug every 4 hours. The graph shows the amount f(t) of the drug in the bloodstream after t hours.

Find

lim t 12f(t)

and

lim t 12+f(t).

lim t 12f(t) =  mg

lim t 12+f(t) =  mg

8.–/2 pointsscalcet7 2.2.024.mi.nvaMy Notes

Use a table of values to estimate the value of the limit. If you have a graphing device, use it to confirm your result graphically.lim x0

9.–/2 pointsscalcet7 2.2.030.mi.nvaMy Notes

Determine the infinite limit.lim x10

    

10.–/2 pointsscalcet7 2.2.038.nvaMy Notes

Find the vertical asymptotes of the function.y =


Confirm your answer by graphing the function.

11.–/2 pointsscalcet7 2.2.041.nvaMy Notes

(a) Estimate the value of the limit

lim x0 (1 + x)1/x

to five decimal places.


(b) Illustrate part (a) by graphing the function

y = (1 + x)1/x.

12.–/2 pointsscalcet7 2.2.046.nvaMy Notes

In the theory of relativity, the mass of a particle with velocity v ism =

,where m0 is the mass of the particle at rest and c is the speed of light. What happens as

v c?

m

m

    

m m0

m 0

Question Part Points Submissions Used x

Explanation / Answer

1. Please note that limit of a function will exist only if the left hand limit and the right hand limit of a function are equal.

We are given that the left hand limit for f(x) that is as x approaches 9 from left is = 6

and the right hand limit for f(x) that is as x approaches 9 from the right is = 3

Hence the answer is

No, lim x9 f(x) cannot exist if lim x9f(x) lim x9+f(x).

2. Please note the holes in the grapg imply that the function is not defined at that particular va;ue of x. Like

In our graph at x = 2 the function does not exits.

However as x approaches 2 from the left the function approaches 4 and when x approaches 2 from the right the function approaches 3.

Hence the limit does not exist as x approaches 2

=>

(a) lim x 2g(x) = 4      and    (b) lim x 2+g(x) = 3 .

(c) Since the left and right limits are different, we conclude that the limit as x approaches 2 of g(x) does not exist.

Next the solid dot in the graph represent that the value of the function when x = 5 is = 3

And as x approaches 5 from the left the function approaches 4 and when x approaches 5 from the right the value of the function approaches 4.

Hence the limit exists as x aapraches 5 and is = 4

=>

(d) lim x 5g(x) = 4      and    (e) lim x 5+g(x) = 4 .

(f) This time, the left and right limits are the same and so, by this theorem, we have

lim x 5 g(x) = 4

Despite this fact, notice that g(5) 4.