Simplify fraction in derivative

Hello,

The work done here is really great. May be you can help me with two issues.

`math.derivative('sqrt(6x)','x').toTex() // "\\frac{6}{2\\cdot\\sqrt{6~ x}}"`

How can I have "\\frac{3}{\\sqrt{6x}}" ?

`math.simplify('4x^2+-2x+-6').toTex() // "4~{ x}^{2}-2\\cdot x+-6"`

How can I have "4x^2-2x-6" ?

Sometime polynoms are not properly ordered.
`math.simplify('4x^2+2x-6').toTex() // 4~{ x}^{2}-6+2~ x"`

Thanks