Question

find the rule of :
5,15,45,......,3645

Answer 1

Multiply 5 by 3 = 15. Multiply 15 by 3 = 45. Multiply 45 by 3 = 135. Multiply 135 by 3 = 405. Multiply 405 by 3 = 1215. Multiply 1215 by 3 = 3646. So multiply your final number by 3.

Answer 2

but how would i write that as an equation? i have to use sigma notation to find the sum of the terms

Answer 3

Maybe this is it?

Answer 4

it's getting close! haha i think that's the right idea...thanks for the help!