【One topic per day】Sum of the first nth term of Series

前端题库,Javascript题集

Posted by Jerry on March 25, 2019

Sum of the first nth term of Series

Task: Your task is to write a function which returns the sum of following series upto nth term(parameter).

Series: 1 + 1/4 + 1/7 + 1/10 + 1/13 + 1/16 +...

Rules:

  • You need to round the answer to 2 decimal places and return it as String.
  • If the given value is 0 then it should return 0.00
  • You will only be given Natural Numbers as arguments. Examples:
    SeriesSum(1) => 1 = "1.00"
    SeriesSum(2) => 1 + 1/4 = "1.25"
    SeriesSum(5) => 1 + 1/4 + 1/7 + 1/10 + 1/13 = "1.57"
    

Reply

SeriesSum = num => {
    let sum = 0;
    for(let i=0;i<num;i++)sum += 1/(i*3 + 1);
    return sum.toFixed(2);
}

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