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How much is ∑(1/(√j + √(j + 1)) (j=0..n)?

5 Answers

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  • 7 years ago
    Favorite Answer

    The response is√(n+1).

    To simplify, you have ∑a_j

    Multiply numerator and denominator in a_j by √(j+1) - √j. You will see that a_j is actually √(j+1) - √j. When you do the sum, √(j+1) from a_j is canceled by -√(j+1) of a_(j+1).

  • 7 years ago

    Rationalize the denominator:

    1 / [√(j+1) + √j] = [√(j+1) - √j] / [(j+1) - j]

    1 / [√(j+1) + √j] = √(j+1) - √j

    In a sum, the positive part of each term is canceled by the negative part of the next term. With the sum from j=0 to n:

    ∑ 1 / [√(j+1) + √j] = [√1 - √0] + [√2 - √1] + ... + [√(n+1) - √n]

    = √(n+1) - √0

    ∑ 1 / [√(j+1) + √j] = √(n+1)

  • Anonymous
    7 years ago

    Using a convergence test letting n go off to infinity, you will find that your equation doesn't converge to a particular number. We would say that your series is 'divergent'

    However if you used a partial sum formula , you will find that your above equation settles on the value √(n+1)

    Hope this helps

  • Anonymous
    7 years ago

    What the fvck is that? O.O

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  • 7 years ago

    j=1028 just kidding... i dont know...

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