Evaluate the sum:
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Notice that $\displaystyle \sum_{k=50}^{300} = \sum_{k=1}^{300 }- \sum_{k=1}^{49 }$ and $\displaystyle \sum_{k=1}^n k^3 = \frac{ (n(n+1))^2 }{4} $
Originally Posted by simplependulum Notice that $\displaystyle \sum_{k=50}^{300} = \sum_{k=1}^{300 }- \sum_{k=1}^{49 }$ and $\displaystyle \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
Originally Posted by tbenne3 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.
got it right nevermind
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