So far, I used the definition of floors to provide an interval. Then I did some algebra in order to get $(n-1)/2$. And I am able to deduce that $\lfloor n/2 \rfloor > (n-1)/2$, but now I'm stuck on proving them to be equivalent to each other.

$$(n/2) - 1 < \lfloor n/2 \rfloor \leq n/2$$ $$\lfloor n/2 \rfloor > (n-2)/2$$ $$\lfloor n/2 \rfloor -1/2 > (n-1)/2$$

Thus, $\lfloor n/2 \rfloor > (n-1)/2$.

But how do I prove that they could also be equivalent to each other?


When $n$ is even, $\lfloor n/2 \rfloor = n/2$.

When $n$ is odd, $n/2 = (n-1)/2 +1/2$. Since $n-1$ is even, $(n-1)/2$ is an integer and $1/2$ is a fraction. Thus, $\lfloor n/2 \rfloor = (n-1)/2$.

  • $\begingroup$ Thank you very much. $\endgroup$ – Mark Park Mar 14 at 0:50

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