Question: Change equation to quartic function and quadratic function in maple

Hi,

Thank you all for participating to my questions before.

I was wondering if we can change an equation into quartic form or quadratic form in maple.

I have succesfully got an equation like the following:

`S__2 ` = sin(alpha - phi)*sin(-beta + alpha)*(gamma*H^2*sin(beta - varepsilon)*sin(alpha) - h^2*sin(beta)*sin(alpha - varepsilon)*gamma + h^2*sin(beta)*sin(alpha - varepsilon)*psi)/(2*sin(-beta - delta - phi + alpha)*sin(beta)^2*sin(alpha - varepsilon)*sin(alpha)) - S__1

From the paper I studied, they change it to form an equation like this

`S__2 ` = 1/2*gamma*H^2*sin(beta - alpha)*(M__3(X)^3 + M__2(X)^2 + M__1*X)/(sin(beta)^2*(D__3(X)^3 + D__2(X)^2 + D__1*X + D__0)) - S__1

Where value of M, D and X is sets of long equation. Can someone teach me how to assign maple to change this kind of equation to another form of equation. It's good enough if I can learn how to learn the basic.

Thank you.

Regards

Faiz Farhan