999999em;"></span><span class="strut bottom" style="height:1.1141079999999999em;vertical-align:-0.25em;"></span><span class="base displaystyle textstyle uncramped"><span class="mord mathit" style="margin-right:0.10764em;">f</span><span class="mopen">(</span><span class="mord mathit">x</span><span class="mclose">)</span><span class="mrel">=</span><span class="mord"><span class="mord mathit">x</span><span class="vlist"><span style="top:-0.413em;margin-right:0.05em;"><span class="fontsize-ensurer reset-size5 s