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Math Help - evaluate the sum

  1. #1
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    evaluate the sum

    Evaluate the sum:
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  2. #2
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    Notice that

     \sum_{k=50}^{300} = \sum_{k=1}^{300 }- \sum_{k=1}^{49 }


    and  \sum_{k=1}^n k^3 =  \frac{ (n(n+1))^2 }{4}
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  3. #3
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    Quote Originally Posted by simplependulum View Post
    Notice that

     \sum_{k=50}^{300} = \sum_{k=1}^{300 }- \sum_{k=1}^{49 }


    and  \sum_{k=1}^n k^3 =  \frac{ (n(n+1))^2 }{4}
    so I substitute 300 and 49 for the n? I tried that but it says I got the wrong answer
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  4. #4
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    Quote Originally Posted by tbenne3 View Post
    so I substitute 300 and 49 for the n? I tried that but it says I got the wrong answer
    Then show all your working so that we can see where you might have gone wrong.
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  5. #5
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    got it right nevermind
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