<math xmlns='http://www.w3.org/1998/Math/MathML'><semantics><mrow xref='id18'><mrow xref='id16'><mrow xref='id8'><mrow><mn xref='id1'>2</mn><mo>⁢</mo><mi xref='id2'>x</mi></mrow><mo>⁢</mo><mfenced><mrow xref='id7'><mfrac><mo>ⅆ</mo><mrow><mo>ⅆ</mo><mi xref='id3'>x</mi></mrow></mfrac><mrow xref='id6'><mi xref='id4'>y</mi><mo>⁡</mo><mfenced><mi xref='id5'>x</mi></mfenced></mrow></mrow></mfenced></mrow><mo>+</mo><mrow xref='id15'><mfrac><mo>ⅆ</mo><mrow><mo>ⅆ</mo><mi xref='id9'>x</mi></mrow></mfrac><mrow xref='id14'><mfrac><mo>ⅆ</mo><mrow><mo>ⅆ</mo><mi xref='id10'>x</mi></mrow></mfrac><mrow xref='id13'><mi xref='id11'>y</mi><mo>⁡</mo><mfenced><mi xref='id12'>x</mi></mfenced></mrow></mrow></mrow></mrow><mo>=</mo><mn xref='id17'>0</mn></mrow><annotation-xml encoding='MathML-Content'><apply id='id18'><eq/><apply id='id16'><plus/><apply id='id8'><times/><cn id='id1' type='integer'>2</cn><ci id='id2'>x</ci><apply id='id7'><diff/><bvar><ci id='id3'>x</ci></bvar><apply id='id6'><ci id='id4'>y</ci><ci id='id5'>x</ci></apply></apply></apply><apply id='id15'><diff/><bvar><ci id='id9'>x</ci></bvar><apply id='id14'><diff/><bvar><ci id='id10'>x</ci></bvar><apply id='id13'><ci id='id11'>y</ci><ci id='id12'>x</ci></apply></apply></apply></apply><cn id='id17' type='integer'>0</cn></apply></annotation-xml><annotation encoding='Maple'>2*x*diff(y(x),x)+diff(diff(y(x),x),x) = 0</annotation></semantics></math>