Question 1085362: the first numbers p-1, 2p-2 and 3p-1 are the first three terms of a GP where p>0 find
(i) the value of p
Answer by rothauserc(4718)   (Show Source):
You can put this solution on YOUR website! p-1, 2p-2, 3p-1
:
a(1) = p-1
a(2) = 2p-2 = (p-1) * r
a(3) = 3p-1 = (p-1) * r^2
:
(p-1) * r = 2 * (p-1)
r = 2
:
3p-1 = (p-1) * 2^2
:
3p-1 = 4p-4
:
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p = 3
:
check answer
:
3-1, 2*3-2, 3*3-1
:
2, 4, 8
:
our answer checks
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