### review4

```Math 165/166
Review 4
Name & Number:
Show all your work to get proper credits. Otherwise, no credit will be given. This is only the review for
exam and you should review other necessary work. Exam 4 covers sections 4.1,4.3,4.4,6.1-6.5.
1. Find the amount s of advertising that maximizes the profit P  0.1s 2  6s  100 , where s and P
are measured in thousands of dollars and what is the maximum profit, then?
2. Fill in the table so it is exponential data and find its formula.
x 0
y 2.60
2
4
210.6
631.8
3. Sketch the following functions. Label them clearly.
(a) y  ( x  1)2
(b) y  ( x  2)2  1
(d) y  log3 x (e) y  ln x  1
(c) y  2 x2  4 x  1
4. (a) Divide 8x3  4 x 2  x  5 by x+3 in two methods, polynomial division,
(b) Use the remainder theorem to verify your remainder obtained in (a) is correct. Is (x+3) a factor of the
polynomial 8x3  4 x 2  x  5 ?
5. The parents of a newborn baby infant place \$10,000 in an investment that pays 8% annual interest
compounded quarterly. What sum is available at the end of 18 years to finance the child’s college
education?
6. Solve the equation for x.
(a) log16 x  1/ 2
(b) 32 x  814/3
(d) log x  log( x  3)  1
(c) log3 ( x  1)  2
(e) log 2 ( x  4)  3  log 2 ( x  2)
7. The Davis National bank pays 6% interest compounded quarterly. How long will it take for a deposit to
triple in value?
8. Suppose that the number N of mopeds sold when x thousands of dollars are spent on advertising is
given by N  4000  1000ln( x  2) . How much advertising money must be spent to sell 6000 mopeds?
9. If log2  s , log3  t and log5  u , then express the following in terms of s,t, and u.
(a)
log18 (b) log
5
(c) log1.5 (d) log 7.5
4
10. Fechner’s Logarithmic Law in psychology is used to meausred notable changes in sensory response
based upon eqaul increases of a particular sensory stimulus. The law is given by the equation
S  k log l where S is the maginitude of the sensory experience, l is the physical intensity, and k is a
scaling constant. Determine the physical intensity of a sensory experiment if the recorded magnitude of
sensation is 0.5005 and the constant k  10.
11. A rectangular region with one side against an existing building is to be fenced in. If 100 feet of fencing
material are available, what dimension will maximize the area of the region? What is the maximum area?
1. when x=30(thousands), profit becomes maximum \$190(thousand)
2.
x 0
y 2.60
2
23.4
4
210.6
5
631.8
y  2.6  3x
3.
4. (a) 8x3  4 x2  x  5  (8x2  20 x  59)( x  3)  182 or
8 x3  4 x 2  x  5
182
 8 x 2  20 x  59 
x3
x3
(b) if P( x)  8x3  4 x 2  x  5 , then P(3)  182 and x+3 is not a factor of P(x) because the reaminder
is not eqaul to zero.
5. \$41,611.40
7. 18.5 years
6. (a) 4 (b) 8/3 (c) 10 (d) 5 (e) 1  17
8. \$5389
9. (a) s+2t (b) u-2s (c) t-s (d) 0.5t+0.5u-0.5s
10. 1.122147
11. 25 by 50 and maximum area is 1250 square feet
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