Question

What is the formula for finding a1 in the geometric series sn=48455, r=3.2, n=3?

Answer 1

The formula for finding the sum in the geometric series:
`S_(n)=a_(1) * ( r^(n) -1)/(r-1)` For finding a1:
`a_(1) = ( S_(3)*(3.2-1) )/( 3.2^(3)-1 ) = (48455*2.2)/(32.768-1)= (106601)/(31.768)=3355.6094`