mml=<math xmlns="http://www.w3.org/1998/Math/MathML"><mfrac><mrow><mi>sin</mi><mfenced separators="|"><mrow><mi mathvariant="normal">x</mi><mo>+</mo><mi mathvariant="normal">y</mi></mrow></mfenced></mrow><mrow><mi>sin</mi><mfenced separators="|"><mrow><mi mathvariant="normal">x</mi><mo>-</mo><mi mathvariant="normal">y</mi></mrow></mfenced></mrow></mfrac><mo>=</mo><mfrac><mrow><mi mathvariant="normal">a</mi><mo>+</mo><mi mathvariant="normal">b</mi></mrow><mrow><mi mathvariant="normal">a</mi><mo>-</mo><mi mathvariant="normal">b</mi></mrow></mfrac><mo>&#xA0;</mo></math>