Find 1 + (2 / 3) + (2 / 3) quadratic + (2 / 3) cubic + +The value of (2 / 3) n power

Find 1 + (2 / 3) + (2 / 3) quadratic + (2 / 3) cubic + +The value of (2 / 3) n power

S = 1 + (2 / 3) + (2 / 3) quadratic + (2 / 3) cubic + +(2 / 3) nth power (1)
2 / 3S = (2 / 3) + (2 / 3) quadratic + (2 / 3) cubic + +(2 / 3) n power + (2 / 3) n + 1 power (2)
1 / 3S = S-2 / 3S = (1) - (2) = 1 - (2 / 3) n + 1 power
So: S = 3-2 (n + 1 power) / 3 (n power)