Question

can someone help me with the steps i have an answer just don't know how?
geometric partial sum ∑[i=1,5,3(-4)^(i-1)].

Answer 1

you want to just plug them in i=1,2,3,4,5
3(-4)^(1-1) + 3(-4)^(2-1) + 3(-4)^(3-1) + 3(-4)^(4-1) + 3(-4)^(5-1)

Answer 2

are you looking for a generaly formula? you would need the whole formula