Editing MathML (section)

== Example ==
The well-known [[quadratic formula]] could be represented in Presentation MathML as an expression tree made up from layout elements like {{code|lang=XML|<mfrac>}} or {{code|lang=XML|<msqrt>}}:

<syntaxhighlight lang="xml">
<math mode="display" xmlns="http://www.w3.org/1998/Math/MathML">
<semantics>
	<mrow>
		<mi>x</mi>
		<mo>=</mo>
		<mfrac>
			<mrow>
				<mo form="prefix">&minus;</mo>
				<mi>b</mi>
				<mo>&pm;</mo>
				<msqrt>
					<msup><mi>b</mi><mn>2</mn></msup>
					<mo>&minus;</mo>
					<mn>4</mn><mo>&it;</mo><mi>a</mi><mo>&it;</mo><mi>c</mi>
				</msqrt>
			</mrow>
			<mrow>
				<mn>2</mn>
				<mo>&it;</mo>
				<mi>a</mi>
			</mrow>
		</mfrac>
	</mrow>
	<annotation encoding="application/x-tex"><!-- TeX -->
		x = \frac{-b\pm\sqrt{b^2-4ac}}{2a}
	</annotation>
	<annotation encoding="StarMath 5.0">
		x = {-b plusminus sqrt {b^2 - 4 ac}} over {2 a}
	</annotation>
	<!-- More annotations can be written: application/x-troff-eqn for eqn, application/x-asciimath for AsciiMath... -->
	<!-- Semantic MathML go under <annotation-xml encoding="MathML-Content">. -->
</semantics>
</math>
</syntaxhighlight>

This example uses the {{code|lang=XML|<annotation>}} element, which can be used to embed a semantic annotation in non-XML format, for example to store the formula in the format used by an equation editor such as [[StarMath]] or the markup using [[LaTeX]] syntax. The {{code|encoding}} field is usually a [[MIME type]], although most of the equation encodings don't have such a registration; freeform text may be used in such cases.

Although less compact than other formats, the XML structuring of MathML makes its content widely usable and accessible, allows near-instant display in applications such as [[web browser]]s, and facilitates an interpretation of its meaning in mathematical software products. MathML is not intended to be written or edited directly by humans.<ref>{{cite web
| url = https://www.w3.org/TR/REC-MathML/#abstract
| title = Mathematical Markup Language (MathML) 1.01 Specification (Abstract)
| access-date = 2006-09-26
| first1 = Steven | last1 = Buswell
| first2 = Stan   | last2 = Devitt
| first3 = Angel  | last3 = Diaz
| display-authors = etal
| date = 1999-07-07
| quote = While MathML is human-readable it is anticipated that, in all but the simplest cases, authors will use equation editors, conversion programs, and other specialized software tools to generate MathML.
}}</ref>