SOLUTION: I am struggling with a couple of these types of problems. Not sure how to find results. My on-line instructions hasn't given me a good example. If given A7 = 16 and A11= 256 Find

Algebra ->  Sequences-and-series -> SOLUTION: I am struggling with a couple of these types of problems. Not sure how to find results. My on-line instructions hasn't given me a good example. If given A7 = 16 and A11= 256 Find      Log On


   



Question 140684: I am struggling with a couple of these types of problems. Not sure how to find results. My on-line instructions hasn't given me a good example.
If given A7 = 16 and A11= 256 Find r and A1? Thanks!

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
given A7 = 16 and A11= 256 Find r and A1
a(7) = a(1)*r^6 = 16
a(11)= a(1)*r^10= 256
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Divide 1st into 2nd to get:
r^4 = 16
r = 2
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Substitute into a(1)r^6 = 16 to get:
a(1)*2^6 = 16
a(1)*64 = 16
a(1) = 16/64
a(1) = 4
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Cheers,
Stan H.