Question

find the sum of the first terms of an A. P 1,4,7,10....also find s40​

Answer 1

Answer:

heya mate there's your answer

Given series of AP is 1,4,7,10.....

let first term of the AP be a1 =1

second term of the AP be a2=4

common difference of the AP be d

d=a2-a1

d=4-1

d=3

so common difference of the AP is d =3

Sum of n terms in an AP is,

Sn=n/2[2a1+(n-1)d]

S40=40/2[2×1+(40-1)(3)]

=20[2+39(3)]

=20[2+117]

=20[119]

=2380

hope it helps you ......

Thank you !!