Tuesday, 20 September 2016

How is derived the inductive step in mathematical induction?



I am quite familiar with the algorithm of mathematical induction but I can't rationalize the inductive step very well.
Suppose I have the classical example:
$$0 + 1 +2 + \ldots + n = \frac{n(n+1)}{2}$$
In the inductive step I have to show that this hold for $k+1$ so I don't understand why I don't find written:
$$0 + 1 +2 + \ldots + (k+1) = \frac{(k+1)((k+1)+1)}{2}$$

instead of:
$$0 + 1 +2 + \ldots + k + (k+1) = \frac{(k+1)((k+1)+1)}{2}$$



Why the $k$ in the left-hand side of the equation in not substitute with $k+1$ as in the right-hand side of the equation. How can I rationalize the inductive step of mathematical induction? Can any one prove me that the first equation is also right and show me how to deal with the proof?


Answer




Can anyone prove me that the first equation is also right and show me how to deal with the proof?




Apparently you don't understand that the first and second equations are exactly the same,




$$0+1+\cdots+5$$



and $$0+1+\cdots+4+5$$



are the same things.


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