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    Evaluate: 1+12+14+18+116+⋯\text{ } 1 +\frac{1}{2} + \frac{1}{4} + \frac{1}{8} + \frac{1}{16} + \cdots 1+21​+41​+81​+161​+⋯​
    Question

    Evaluate: 1+12+14+18+116+\text{ } 1 +\frac{1}{2} + \frac{1}{4} + \frac{1}{8} + \frac{1}{16} + \cdots

    A.

    2

    B.

    1/50

    C.

    1/22

    D.

    3

    Correct option is A

    Given:

     1+12+14+18+116+\text{ } 1 +\frac{1}{2} + \frac{1}{4} + \frac{1}{8} + \frac{1}{16} + \cdots

    Formula  Used:

    Sum of terms in an infinite GP  = a(1r)\frac{a}{(1-r)} ​​

    Solution:

     1+12+14+18+116+\text{ } 1 +\frac{1}{2} + \frac{1}{4} + \frac{1}{8} + \frac{1}{16} + \cdots

    This is GP series 

    a = 1 , r = 12\frac{1}{2} ​​

    Sum of the series  = a(1r)\frac{a}{(1-r)}  

    1(11/2)\frac{1}{(1-1/2)}

    = 2 

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