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Homework Statement
Prove that (1*2) + (2*3) + (3*4) + ... + n(n+1) = [tex]\frac{n(n+1)(n+2)}{3}[/tex] for every positive integer n
**edit: using mathematical induction**
Homework Equations
In section 3 I have posted my work so far. the k^3 term is bugging me, I'm not sure how this is going to play out and if I made a mistake. I have two questions:
1) Is my notation alright? Does it look like a proof should look?
2) Can I alter the left hand side of the proof and make it match the right hand side, or should I only be working on matching the right hand side to the left hand side?
Thanks
3. Attempted Solution
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