$fcolonsdrta.netbb R^+ osdrta.netbb R^+$, $f(x) = x^2$ is injective.$fcolonsdrta.netbb R osdrta.netbb R$, $f(x) = x^2$ is not injective given that $(- x)^2 = x^2$.

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what is the difference between $sdrta.netbb R^+$ and $sdrta.netbb R$?

Furthermore, what is the distinction between $sdrta.netbb N$ and also $sdrta.netbb N^+$?



$sdrta.netbb R^+$ commonly denotes the set of positive actual numbers, that is: $$sdrta.netbb R^+ = xinsdrta.netbb Rmid x>0$$

It is also deprovided by $sdrta.netbb R^>0,sdrta.netbb R_+$ and so on.

For $sdrta.netbb N$ and $sdrta.netbb N^+$ the difference is comparable, however it might be non-existent if you define $0 otinsdrta.netbb N$. In many kind of collection concept publications $0$ is a natural number, while in analysis it is regularly not thought about a herbal number. Your mileage might vary on $sdrta.netbb N$ vs. $sdrta.netbb N^+$.


Simply $sdrta.netbb R$ suggests the set of real numbers.

$sdrta.netbb R^+$ suggests the set of positive genuine numbers.

And $sdrta.netbb R^-$ implies the set of negative genuine numbers.


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