Question

Find S15 for the geometric series 72 + 12 + 2 + 1/3 +

Answer 1

finish the equation. please and thank you

Answer 2

Hello,


`u_(1)=72\\ u_(2)=(72)/(6)\\ u_(3)=(72)/(6^(2))\\ u_(15)=(72)/(6^(14))\\ s=72*(1+(1)/(6^(1))+(1)/(6^(2))+(1)/(6^(3))++...+(1)/(6^(14)))\\ =72*(((1)/(6^(15))-1)/((1)/(6)-1)})\\ =72*((470184984576-1)/(78364164095*5))\\ =86,400...`