Question

Algebraic form of an arithmetic sequence is 7n-4
a) what is its first term ?
b) Find its 10th term?​

Answer 1

Answer:

Sn=7n-4

By putting n=1 in the above equation

S1=a1=7×1-4=3

S2=7×2-4=10

S2=a1+a2=3+a2=10

a2=10-3=7

common diff d=a2-a1=7-3=4

a10=a1+(10-1)×d=3+9×4=39

Ans: 1st term=3 and 10th term =39