inverse of a function in matlab

[colorcircle]

hii
does anyone know how to find inverse of a function(curve) in matlab?
i have this curve y=1+q1*(x^2)+q2*x^4
it gives me a curve bent downwards (where q1 and q2 are coefficients )
what i want to do is that find another curve which is just inverse of this curve.
thank you

 

[JoannesPaulus]

If you do not mean the "mathematical inverse" x, but just the negative, then yy=-y ;-)

 

[colorcircle]

and can u tell me sir how to find x using matlab? for above given type of polynomials(using matlab)

 

[JoannesPaulus]

sure: w=x^2, so your equation becomes a second order polinomial: y=1+q1*w+q2*w^2
I believe you can do the rest!