Last question, promise! Not sure how to write out a summation but here it goes: 6 E (1/3)^i+1 i=1 I know this means: (1/3)^(6+1)+(1/3)^(5+1)+(1/3)^(4+1) .....(1/3)^(1+1) but I'm not sure how to write this out and solve?