6d = -24, so d = -4
since d<0, the maximum partial sum is just
a1 = 84+12 = 96
In an A.P. if a4=84 and a10=60 then find the maximum possible partial sum of the sequence.
2 answers
actually, that is wrong.
when do the terms start going negative?
96 - 4n < 0
n > 24
so the greatest partial sum will be
S24 = 24/2 (96+0) = 1152
when do the terms start going negative?
96 - 4n < 0
n > 24
so the greatest partial sum will be
S24 = 24/2 (96+0) = 1152