Let see how to build up this formula that is going to give that term of rank n
1st term =a₁ = To be calculated
1st a₁ = a₁ x r°
2nd a₂ = a₁ x r¹
3rd a₃ = a₁ x r²
4th a₄ = a₁ x r³
5th a₅ = a₁ x r⁴
.......................
.......................
nth : a(n) = a₁ x r⁽ⁿ-¹)
Note when that the subscript of a is the same as the exponent mines 1
As per the table we have:
a₀ =3 =
a₁ =6 = 6
a₂ =12
so r =6+/3 =12/6 = 2
formula: a(n) = a₁ x r⁽ⁿ-¹) ==> a(n) = 3 x 2⁽ⁿ⁻¹⁾
