data/mathtoweb/90.mml
<math xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mstyle displaystyle="true"><munder><mo>∫</mo><mrow><msup><mi>ℝ</mi><mi>n</mi></msup></mrow></munder></mstyle><mi>f</mi><mspace width="0.167em" /><mo>ⅆ</mo><mi>x</mi><mo>=</mo><mstyle displaystyle="true"><munderover><mo>∫</mo><mn>0</mn><mo>∞</mo></munderover></mstyle><mrow><mo rspace="0.3em" lspace="0em" stretchy="true" fence="true" form="prefix">{</mo><mstyle displaystyle="true"><munder><mo>∫</mo><mrow><mo>∂</mo><mi>B</mi><mrow><mo form="prefix">(</mo><msub><mi>x</mi><mn>0</mn></msub><mo>;</mo><mi>r</mi><mo form="postfix">)</mo></mrow></mrow></munder></mstyle><mi>f</mi><mspace width="0.167em" /><mo>ⅆ</mo><mi>S</mi><mo rspace="0em" lspace="0.3em" stretchy="true" fence="true" form="postfix">}</mo></mrow><mspace width="0.167em" /><mo>ⅆ</mo><mi>r</mi></mrow></math>