Question

Evaluate the summation of 25 times 0.3 to the n plus 1 power, from n equals 2 to 10.

Answer 1

a1=25(0.3)^2, common ratio = 0.3

So sum of first n terms of a geometric series = a1(1-r^n)/(1-r)

So sum of frist 10 terms of the given series = 25(0.3)^2(1-0.3^10)/ (1-0.3)

So sum of n=2 to n=10 is : 25(0.3)^2(1=0.3^10)/(1-0.3) -25(0.3)^2= 0.96426673425