Question

The sum of n terms of an ap is sn =2nsquare +6n find the first term and the common difference

Answer 1

Answer:

sn=2n²+6n

S1=2(1)²+6(1)=8=a=first term

S2=2(2)²+6(2)=8+12=20=a+a2

=>a2=20-a=20-8=12

d=a2-a=12-8=4