Question

3 + 3(7) + 3(7^2) + 3(7^3)...+7^n x (2)
Simplify using geometric sum formula...?

Answer 1

r u sure last term is 7^n x (2)

Answer 2

Yeah...I'm actually just trying to simplify this formula to be in a form I can use for a recursion formula. I would group the first terms and simplify then add the last term in...

Answer 3

ok if thats the case
then forcefully add one more 7^n x
and now use that result

Answer 4

I don't understand...?

Answer 5

it is like this
3 + 3(7) + 3(7^2) + 3(7^3)...+(7^n x (2)+7^n x)-7^n x
then it will become
(3 + 3(7) + 3(7^2) + 3(7^3)...+(7^n x (3)) -7^nx
now simplify it using
a*((r^n-1)/(r-1)) of gp
at last u will be having -7^nx