1. ## evaluate the sum

Evaluate the sum:

2. Notice that

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

and $\displaystyle \sum_{k=1}^n k^3 = \frac{ (n(n+1))^2 }{4}$

3. 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

4. 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.

5. got it right nevermind