mml=<math xmlns="http://www.w3.org/1998/Math/MathML"><mi>x</mi><mo>=</mo><msqrt><mi>a</mi><mroot><mrow><mi>b</mi><msqrt><mi>a</mi><mo> </mo><mroot><mi>b</mi><mn>3</mn></mroot></msqrt></mrow><mn>3</mn></mroot></msqrt><mo>.</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>.</mo><mo>∞</mo></math>