eval - Maple Help
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Units[Standard]

 eval
 evaluate at a point

Calling Sequence

 eval(expr, x = a) $\genfrac{}{}{0}{}{\mathrm{expr}}{\phantom{x=a}}|\genfrac{}{}{0}{}{\phantom{\mathrm{expr}}}{x=a}$ eval(expr, eqns)

Parameters

 expr - algebraic expression x - usually name, but may be general expression a - algebraic expression eqns - set or list of equations

Description

 • In the Standard Units environment, the eval function is overloaded to evaluate an expression after removing the units, and then combine the result with the units.
 • For other properties, see the global function eval.

Examples

 > $\mathrm{with}\left({\mathrm{Units}}_{\mathrm{Standard}}\right):$

The following defines velocity in terms of the acceleration_of_free_fall unit ($\mathrm{gn}$) and the variable height.

Notes:

 – To enter a unit in 2-D Math input, select the unit from the appropriate Units palette. If the unit you want is not there, select $\mathrm{unit}$ and then enter the unit.
 – When you edit a unit, double brackets appear around it.
 > $\mathrm{velocity}≔\sqrt{2⟦'\mathrm{gn}'⟧\mathrm{height}}$
 ${\mathrm{velocity}}{≔}\sqrt{{2}}{}\sqrt{{\mathrm{height}}}{}⟦\sqrt{{\mathrm{gn}}}⟧$ (1)
 > $\genfrac{}{}{0}{}{\mathrm{velocity}}{\phantom{\mathrm{height}=3⟦'\mathrm{ft}'⟧}}\phantom{\rule[-0.0ex]{0.3em}{0.0ex}}|\phantom{\rule[-0.0ex]{0.1em}{0.0ex}}\genfrac{}{}{0}{}{\phantom{\mathrm{velocity}}}{\mathrm{height}=3⟦'\mathrm{ft}'⟧}$
 $\frac{\sqrt{{3}}{}\sqrt{{2}}{}\sqrt{{381}}{}\sqrt{{196133}}}{{5000}}{}⟦\frac{{m}}{{s}}⟧$ (2)
 > $\mathrm{evalf}\left(\right)$
 ${4.234902778}{}⟦\frac{{m}}{{s}}⟧$ (3)
 > $\genfrac{}{}{0}{}{\mathrm{velocity}}{\phantom{\mathrm{height}=0.03⟦'\mathrm{km}'⟧}}\phantom{\rule[-0.0ex]{0.3em}{0.0ex}}|\phantom{\rule[-0.0ex]{0.1em}{0.0ex}}\genfrac{}{}{0}{}{\phantom{\mathrm{velocity}}}{\mathrm{height}=0.03⟦'\mathrm{km}'⟧}$
 ${0.01732050808}{}\sqrt{{2}}{}\sqrt{{196133}}{}\sqrt{{5}}{}⟦\frac{{m}}{{s}}⟧$ (4)
 > $\mathrm{evalf}\left(\right)$
 ${24.25693715}{}⟦\frac{{m}}{{s}}⟧$ (5)

 See Also