Question

find the sum of all 11 terms of an ap -3, -1/2,2.....

Answer 1

Hi Mate!!!

Sum of n terms in an ap is

Sn = n/2 { 2a + (n-1 ) d }

n =11 ,. a = -3 and d = 5/2

S11 = 11/2 { -6 + ( 10 ) × 5/2}

S11 = 104.5

Have a nice time