Question 944648: please help solve these two problems:
sequence 4,8,16,32,64,128
d=2
a sub 1=4
prob #1: a(3) what is a? is that the same as a sub exponent 1 which is 4?
prob #2: a(1)+a(7)
Thank you
Found 2 solutions by stanbon, MathLover1:
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! please help solve these two problems:
sequence 4,8,16,32,64,128
Note:: This is a Geometric Sequence
r = 8/4 = 2
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a(1) = 4
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prob #1: a(3) what is a?
a(3) = a*r^2 = 4*2^2 = 16
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prob #2: a(1)+a(7) = 4 + 4*r^6 = 4 + 4*2^6 = 4+4*64 = 4+256 = 260
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Cheers,
Stan H.
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Answer by MathLover1(20850)  (Show Source):
You can put this solution on YOUR website!
sequence  , , , , ,
 ---> common multiplier
 sub  = => sub = which is first term in sequence and first term is
prob #1: => third term which is ; so, 
prob #2:
=> we need general formula to find 
sequence ,,,,,
using common multiplier could be written as  ,  , ,  ,  ..... 
so, general formula is:
 (for all terms given) where  is the number of the term
now find
and will be
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