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transgalactic
Nov27-08, 04:36 PM
i am given a real and positive number a1 a2 a3 ...
which goes by a(n)<=c*a(n-1) for every n=>2 for a certain given number c>0 .

prove that
a(n)<=a(1)*c^(n-1)

??

a(n) is the n'th number of the series

nicksauce
Nov27-08, 04:55 PM
Use a proof by induction. It should be fairly straight forward.

transgalactic
Nov27-08, 05:00 PM
i dont have a base case here

and there are two variables

??

VeeEight
Nov27-08, 05:03 PM
Use induction of n. Your base case would be n=2.

transgalactic
Nov27-08, 05:04 PM
for n=2
i get
a(2)=c*a(1)

this base case doesnt prove anything

??

nicksauce
Nov27-08, 05:17 PM
The base case is trivially true, since it is the same condition for the members of the sequence.