= Right derivative
{title2=$f'_+(a)=\lim_{h\downarrow0}\dfrac{f(a+h)-f(a)}h$}
The <right derivative> is the displayed one-sided <limit>, when it exists as a finite number. It describes differentiation at the left endpoint of a <closed interval> without requiring the <function> to be defined to the left. An ordinary <derivative> at an interior point requires matching left and right <derivatives>. For example, the <absolute value> <function> has right derivative one at zero and left derivative minus one, so it has no ordinary <derivative> there.
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