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JEE Main201815 Apr 2018Morning ShiftMathematicsSequences and SeriesActual

If b is the first term of an infinite G. P whose sum is five, then b lies in the interval.

Options

  1. A(- ,-10)
  2. B(10, )
  3. C(0,10)
  4. D(-10,0)

Correct answer

C. (0,10)

Step-by-step solution

First term =b and common ratio = r For infinite series, Sum = b 1-r =5 b=5(1- r ) So, interval of b=(0,10) as, -1 < r < 1 for infinite GP.

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