Question

If the sum to n terms pf an
a.P is sn=3n+2n2 then the common difference

Answer 1

Step-by-step explanation:

the answer is in image. Hope it helps.

Answer 2

Answer:

Given,

Sn = 3n + 2n^2

so,

S1 = 3×1 + 2×1^2

S1 = 5

We know, S1 = a1

so a1 = 5

Now S2 = 3(2) +2(2)^2

S2 = 6 + 8 = 14

Also,

S2 = a1 + a2,

or, a2 = S2 - a1 = 14 - 5 = 9

Now, common diff. = a2 - a1 = 9 - 5 = 4.

Hence 4 is the common diff. of the given A.P.

I hope you understood. You may ask if you have doubts :)