MTH 120 — Summer — 2005
Essex County College — Division of Mathematics
Quiz # 21— May 11, 2005
Name:
Signature:
Show all work clearly and in order, and box your final answers. Justify your answers algebraically
whenever possible. You have 20 minutes to take this 10 point quiz. When you do use your
calculator, sketch all relevant graphs and write down all relevant mathematics.
1. Given that
Pk=k
2
·[5k−3] ,
find Pk+1.
Solution: Just replace kwith (k+ 1).
Pk+1 =(k+ 1)
2
·[5 (k+ 1) −3] .
2. Find the rational number representation of the given repeating decimal.
1.287
Solution: Let x= 1.287.
10x= 12.87
1000x= 1287.87
1000x−10x= 1287.87 −12.87
990x= 1275.0000
x=1275
990
3. Use summation notation to write the given sum.
3+9+27+81+· · · + 729
Solution: Here’s one possible answer.
3+9+27+81+· · · + 729 =
6
X
n=1
3n
1This document was prepared by Ron Bannon using L
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