Please help!! I honestly have no idea how to do this. $$\sum_{i=1}^{\infty} 6(3)^{i-1}$$ find the 7th partial sum

Question

Please help!! I honestly have no idea how to do this. $$\sum_{i=1}^{\infty} 6(3)^{i-1}$$  find the 7th partial sum

anonymous · Answer

isnt that a GP?

anonymous · Answer

What's a GP? @divu.mkr

anonymous · Answer

gp is a sequence in which each term have a constant ratio with the next one

anonymous · Answer

in this ques is 3

anonymous · Answer

Yes i understand that I just call that the constiant ratio, ive ever heard it called the gp

anonymous · Answer

yep.... in this question just take out 6 out of sigma and sum of a gp is a(1-r^n)/(1-r)

anonymous · Answer

I have no idea what youre doing. I was taught that im suppose to do something and plug the information iinto the arithmetic formula Sn=$$s _{n}= (n/2) (a_{1}+a_{n})$$