Question

is it necessary to find an if sn is given as 5n²+3n and asked to find 'd' and 'a'​

Answer 1

Answer:

No, just let n

Let n values as 1,2,3

then you can find a and d

Answer 2

put n=1

then put n=2

S1 is always equal to a1

A2=S2-S1

then d=A2-A1