ЁЯУв Too many exams? DonтАЩt know which one suits you best? Book Your Free Expert ЁЯСЙ call Now!

    Question

    Find sum of first n terms: 2 + 6 + 12 + 20 + 30 +

    тАж
    A n(n-2)(n+1)/3 Correct Answer Incorrect Answer
    B n(n+1)(n+2)/3 Correct Answer Incorrect Answer
    C n(n+1)(n-2)/5 Correct Answer Incorrect Answer
    D n(n-1)(n-2)/3 Correct Answer Incorrect Answer

    Solution

    ATQ,

    Series = n(n+1). Sum = ╬гn(n+1) = ╬гn┬▓ + ╬гn = [n(n+1)(2n+1)/6] + [n(n+1)/2] =┬а n(n+1)(2n+1+3)/6 = n(n+1)(n+2)/3

    Practice Next
    More Series Questions
    ask-question