Some induction proof (1 Viewer)

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This was in our first asst...which I lost marks on. Anyway I was looking through the proof again and tried it again...Does it work?

Prove by induction



The solution gave

Photo0352.jpg

In the inductive step, they say



My question is...is that even proving the case when the LHS is in between? If you know what I mean... That is, by putting . I have imagined a number line like this.

induction question.jpg

It doesn't account for the two cases...??? Only case 2 would prove the result is true, but with 1 you don't know exactly where LHS is

Thanks for any insights or solution.


NB THERE IS A TYPO (k+1)^2 instead of (k+1)^3 but it does not change the solution.
 

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Yay!

Too bad I can't turn back time to when we got our tests back...maybe I could rank 1st..lol

Thanks carrot, I will tell my teacher...
 

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