Find the sum of the following series 2+10+50+,,,,,,,,,,,,,+1250

Mathematics

ScanSolve AI Answer

Answer

1562

Step-by-step solution

3 steps

Let's find the sum of this series.

  1. Identify the first term, common ratio, and the last term.

    The first term is a=2a = 2.
    To find the common ratio rr, divide the second term by the first term:
    r=102=5r = \frac{10}{2} = 5
    The last term is L=1250L = 1250.

  2. Find the number of terms (nn) in the series.

    The formula for the n-th term of a geometric progression is an=a⋅rn−1a_n = a \cdot r^{n-1}.
    We have an=1250a_n = 1250, a=2a = 2, and r=5r = 5.

    1250=2⋅5n−11250 = 2 \cdot 5^{n-1}

    Divide both sides by 2:

    625=5n−1625 = 5^{n-1}

    We know that 54=6255^4 = 625.
    So, 5n−1=545^{n-1} = 5^4.
    Equating the exponents:

    n−1=4n-1 = 4 n=5n = 5

    There are 5 terms in the series.

  3. Calculate the sum of the series.

    The formula for the sum of the first nn terms of a geometric progression is Sn=a(rn−1)r−1S_n = \frac{a(r^n - 1)}{r - 1}.
    Substitute the values a=2a = 2, r=5r = 5, and n=5n = 5:

    S5=2(55−1)5−1S_5 = \frac{2(5^5 - 1)}{5 - 1} S5=2(3125−1)4S_5 = \frac{2(3125 - 1)}{4} S5=2(3124)4S_5 = \frac{2(3124)}{4} S5=62484S_5 = \frac{6248}{4} S5=1562S_5 = 1562

    The sum of the series is 1562.

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