<math xmlns='http://www.w3.org/1998/Math/MathML'><semantics><mrow xref='id15'><mrow xref='id13'><mrow><mo>-</mo><mrow xref='id5'><mi xref='id1'>x</mi><mo>⁢</mo><mrow xref='id4'><mi xref='id2'>y</mi><mo>⁡</mo><mfenced><mi xref='id3'>x</mi></mfenced></mrow></mrow></mrow><mo>+</mo><mrow xref='id12'><mfrac><mo>ⅆ</mo><mrow><mo>ⅆ</mo><mi xref='id6'>x</mi></mrow></mfrac><mrow xref='id11'><mfrac><mo>ⅆ</mo><mrow><mo>ⅆ</mo><mi xref='id7'>x</mi></mrow></mfrac><mrow xref='id10'><mi xref='id8'>y</mi><mo>⁡</mo><mfenced><mi xref='id9'>x</mi></mfenced></mrow></mrow></mrow></mrow><mo>=</mo><mn xref='id14'>0</mn></mrow><annotation-xml encoding='MathML-Content'><apply id='id15'><eq/><apply id='id13'><plus/><apply><minus/><apply id='id5'><times/><ci id='id1'>x</ci><apply id='id4'><ci id='id2'>y</ci><ci id='id3'>x</ci></apply></apply></apply><apply id='id12'><diff/><bvar><ci id='id6'>x</ci></bvar><apply id='id11'><diff/><bvar><ci id='id7'>x</ci></bvar><apply id='id10'><ci id='id8'>y</ci><ci id='id9'>x</ci></apply></apply></apply></apply><cn id='id14' type='integer'>0</cn></apply></annotation-xml><annotation encoding='Maple'>-x*y(x)+diff(diff(y(x),x),x) = 0</annotation></semantics></math>