Overview of the Units[Standard] Subpackage - Maple Help

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Overview of the Units[Standard] Subpackage

Basic Functionality

 • The Units[Standard] subpackage provides an environment that allows users to work with units in their computations. The with(Units[Standard]) command establishes an environment in which some functions, including the ones for basic arithmetic, are modified to accept input with units.
 • To use the Standard Units environment, enter units using the Unit command, *Unit(unit_name).
 • When using the Units[Standard] package, units will by default be converted to your selected unit system. (The default system is SI, the metric system.)
 • The with(Units[Standard]) command does not allow the use of the short form of the Units package commands that customize the dimensions, units, and systems of units. It is necessary to enter the with(Units) command. For a list of the commands in the Units package, see Units.

Accessing the Standard Units Environment

 • To include units in an expression or to use a redefined Units[Standard] subpackage command in the current Maple session, enter the with(Units[Standard]) command first.
 Note: In Maple 2015 and later versions, units are not surrounded by double brackets.
 > with(Units[Standard]):
 > 3*Unit('cm') + 2*Unit('m');
 $\frac{{203}}{{100}}{}⟦{m}⟧$ (1)

Redefined Standard Units Environment Commands

 The commands redefined in the Standard Units environment to accept input with units are:

 To display the help page for a particular command, click the corresponding hyperlink.
 • For more information on the interaction of these commands, see the Standard Units Example Worksheet.

Examples

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.
 – In Maple 2015 and later versions, the double brackets around a unit are not displayed unless you are editing the unit.
 > $\mathrm{with}\left(\mathrm{Units}[\mathrm{Standard}]\right):$
 > $\mathrm{a_length}≔2⟦'m'⟧$
 ${\mathrm{a_length}}{:=}{2}{}⟦{m}⟧$ (2)
 > $\mathrm{a_width}≔3⟦'m'⟧$
 ${\mathrm{a_width}}{:=}{3}{}⟦{m}⟧$ (3)
 > $\mathrm{an_area}≔\mathrm{a_length}\mathrm{a_width}$
 ${\mathrm{an_area}}{:=}{6}{}⟦{{m}}^{{2}}⟧$ (4)

If an input has only one unit, the output uses that unit. If an input has more than one unit, the output is automatically converted to the default unit in the current system of units. The default system of units in the Units package is SI. To change the default system of units, use the UseSystem command.

 > $3{x}^{4}⟦'\mathrm{ft}'⟧+4xy{\left(y-x\right)}^{2}⟦'\mathrm{ft}'⟧$
 $\left({3}{}{{x}}^{{4}}{+}{4}{}{x}{}{y}{}{\left({y}{-}{x}\right)}^{{2}}\right){}⟦{\mathrm{ft}}⟧$ (5)
 > $3{x}^{4}⟦'m'⟧+4xy{\left(y-x\right)}^{2}⟦'\mathrm{ft}'⟧$
 $\left({3}{}{{x}}^{{4}}{+}\frac{{762}}{{625}}{}{x}{}{y}{}{\left({y}{-}{x}\right)}^{{2}}\right){}⟦{m}⟧$ (6)
 > $\mathrm{diff}\left(,x⟦'s'⟧\right)$
 $\left({12}{}{{x}}^{{3}}{+}\frac{{762}}{{625}}{}{y}{}{\left({y}{-}{x}\right)}^{{2}}{-}\frac{{1524}}{{625}}{}{x}{}{y}{}\left({y}{-}{x}\right)\right){}⟦\frac{{m}}{{s}}⟧$ (7)
 > $\mathrm{collect}\left(,x\right)$
 $\left({12}{}{{x}}^{{3}}{+}\frac{{2286}}{{625}}{}{y}{}{{x}}^{{2}}{-}\frac{{3048}}{{625}}{}{{y}}^{{2}}{}{x}{+}\frac{{762}}{{625}}{}{{y}}^{{3}}\right){}⟦\frac{{m}}{{s}}⟧$ (8)
 > $\cdot 625$
 $\left({7500}{}{{x}}^{{3}}{+}{2286}{}{{x}}^{{2}}{}{y}{-}{3048}{}{x}{}{{y}}^{{2}}{+}{762}{}{{y}}^{{3}}\right){}⟦\frac{{m}}{{s}}⟧$ (9)
 > $\mathrm{convert}\left(,'\mathrm{units}',\frac{'\mathrm{mi}'}{'h'}\right)$
 $\left(\frac{{23437500}}{{1397}}{}{{x}}^{{3}}{+}\frac{{56250}}{{11}}{}{y}{}{{x}}^{{2}}{-}\frac{{75000}}{{11}}{}{{y}}^{{2}}{}{x}{+}\frac{{18750}}{{11}}{}{{y}}^{{3}}\right){}⟦\frac{{\mathrm{mi}}}{{h}}⟧$ (10)
 > $\mathrm{eval}\left(,\left[x=3⟦'s'⟧,y=4⟦'\mathrm{min}'⟧\right]\right)$
 ${10012333860}{}⟦{{s}}^{{2}}{}{m}⟧$ (11)