<md>

<md> is a Display Math component that renders a block of aligned display mathematics when used in combination with the <mrow> component.

Attributes and Properties

Examples

Example: <md> with nested <mrow> children

The data contained within an <md> block must be contained in an <mrow>. Equations and content will align vertically where the & symbol is entered in each row.

Example: <md> cannot contain <answer>

An <md> block cannot contain an <answer>. An input on its own can be written into a row, though, and an <answer> outside the display can check it — see the next example.

Example: an input inside <md>, checked by an <answer> outside

The input is drawn inside the aligned display where it was written, and the <answer> refers to it by name and checks what was entered. The input needs no <shortDescription>: its own row describes it to a screen reader, as “x = blank”.

Example: filling in a step of a derivation

A <textInput/>, a <mathInput/>, or an inline <choiceInput/> written inside an <mrow> is rendered in place, inside the aligned display, so the reader completes the missing step where it belongs, and the rows stay aligned at the & around it. Use a <mathInput/> when the missing step is mathematics the reader should write as mathematics; the display makes room for it as it grows, and closes back up as it shrinks.

Without a <shortDescription>, the input is described to a screen reader by its own row alone — here, “f’(x) = blank” — not by the whole display, so no accessibility violation is reported. In this example, the <shortDescription> given replaces that default.

The same restrictions apply as inside <m>: a non-inline <choiceInput/>, an expanded <textInput/> or one given a relative width (in % or em), and any input in a display drawn on a <graph> cannot be placed inside the display. Those inputs are not shown, and a warning explains the problem.

Example: <md> with referenced <math>

<p><m>f(x) = <function name="f" variables="x">x^2</function></m></p>
<p><m>g(y) = <function name="g" variables="y">sqrt(y)</function></m></p>
<p><m>h(z) = <function name="h" variables="z">sin(z)</function></m></p>
 
<p>The first derivatives of functions <m>f(x)</m>, <m>g(y)</m> and <m>h(z)</m> are:
  <md>
    <mrow>\frac{df}{dx} &= 
      <derivative derivVariables="x">$f</derivative>
    </mrow>
    <mrow>\frac{dg}{dy} &= 
      <derivative derivVariables="y">$g</derivative>
    </mrow>
    <mrow>\frac{dh}{dz} &= 
      <derivative derivVariables="z">$h</derivative>
    </mrow>    
  </md>
</p>  

Computational DoenetML components, such as <math>, or <derivative>, can be nested within or referenced within an <md> block.

Exceptions: The <answer> component and other <md> components cannot be nested within an <md> block.

Example: <md> on a <graph>

An <md> block can be placed on a <graph>. The anchor attribute can be used to specify its initial location.

Attribute Examples

Attribute Example: Standard graphical attributes

Since an <md> block can be placed on a graph, the standard graphical attributes draggable, hide, and styleNumber can be used to control its appearance and behavior.

Property Examples

Property Example: latex

The latex property returns the LaTeX code for rendering the equation block.

Property Example: text

The text property returns the text value of the equation block.