Program to find the sum of the series ( 1 / a + 2 / a ^ 2 + 3 / a ^ 3 + ... + n / a ^ n ) | Function to return the sum of the series ; variable to store the answer ; Math . pow ( x , y ) returns x ^ y ; Driver code ; Prlet the sum of the series
function getSum ( a , n ) { let sum = 0 ; for ( let i = 1 ; i <= n ; ++ i ) { sum += ( i / Math . pow ( a , i ) ) ; } return sum ; } let a = 3 , n = 3 ; document . write ( getSum ( a , n ) . toFixed ( 7 ) ) ;