Displaystyle

If you run your private wiki you can allow that users can input formulae in different input formats. Therefore you have to add $wgMathEnableExperimentalInputFormats = true; to your local config. Afterwards you can use two additional input modes which can be enabled via one of the following type attribute

pmml

Presentation MathML

ascii

ASCIIMath

For example asciimath input can be entered via

<math type="ascii">d/dxf(x)=lim_{h->0}(f(x+h)-f(x))/h</math> and looks like Failed to parse (unknown error): {\displaystyle d/dxf(x)=lim_{h->0}(f(x+h)-f(x))/h}