]> MathToWeb (MathML example) MathML generated by MathToWeb
A MathML example displaying a double dot accent representing acceration.

r ¨ = ( x ¨ , y ¨ , z ¨ ) $\mathbf{ \ddot{r} } = (\ddot{x}, \ddot{y}, \ddot{z})$ 

<math xmlns="http://www.w3.org/1998/Math/MathML">
<mrow>
	<mrow mathvariant="bold">
		<mover accent="true">
			<mi>r</mi>
			<mo>&die;</mo>
		</mover>
	</mrow>
	<mo>=</mo>
	<mrow>
		<mo>(</mo>
		<mover accent="true">
			<mi>x</mi>
			<mo>&die;</mo>
		</mover>
		<mo>,</mo>
		<mover accent="true">
			<mi>y</mi>
			<mo>&die;</mo>
		</mover>
		<mo>,</mo>
		<mover accent="true">
			<mi>z</mi>
			<mo>&die;</mo>
		</mover>
		<mo>)</mo>
	</mrow>
</mrow>
</math>