Tell me more ×  Given an expression like  a + b*y + c*y^2 +
d*Sqrt[f + g*y + h*y^2]  How can I programatically, expand this
to a quartic without any fractional powers?  Right now, I am
having to copy and paste it as input expression and manually
move the Sqrt to the RHS and square. I suspect there's an easier
way to do this in Mathematica, perhaps using the Coefficient
function or something similar.  share|improve this question To
make sure I understand the question, you want to automatically
convert the equation A+B*y+C*y^2+D*Sqrt[F+G*y+H*y^2]==0 to the
equation (A+B*y+C*y^2)^2 == D^2 (F+G*y + H*y^2). And you are
fine with the fact that this may introduce extraneous roots (if
your variables are real and Sqrt[] is interpreted as the
positive square root). –  David Speyer Feb 19 at 17:50 Yes
that's correct and I completely accept the consequences. My
expression currently doesn't include the "==0"; however, that
assertion is also true. –  bsdz Feb 19 at 17:54 Maybe you want
Reduce[a + b*y + c*y^2 + d*Sqrt[f + g