extract coefficients

*To*: mathgroup at smc.vnet.net*Subject*: [mg100978] extract coefficients*From*: Galina <Galina.Pilgun at gmail.com>*Date*: Fri, 19 Jun 2009 20:45:02 -0400 (EDT)

Hello all, I have an expression that is nonlinear with respect to variables q [i]. I need to transform it into equation with respect to unknown q[]. Multipliers near each of such combination of q[] are functions that must be extracted for integration. I'm having problem with Coefficient [] because it does not allow extract multipliers near q[i] of just 1- order, combination of the type q[i]q[j] or near q[i]q[j]q[k] Please, help Below there is an example of the expression. I need to transform it into equation with respect to unknown q[1], q[4] and q[7]. w1,v1,u1 are functions of polynomial type that must be integrated numerically to perform a coefficients at q[]. Everything else is numbers in reality. -((EE*h*q[7]*w1[x, y]*Derivative[0, 1][v1][x, y])/(b*R*(-1 + \[Nu] ^2))) - (EE*h*\[Nu]*q[4]*w1[x, y]*Derivative[1, 0][u1][x, y])/(b*R*(-1 + \[Nu]^2)) - (3*q[1]^2*(EE*h*w1[x, y]*Derivative[0, 1][w1][x, y]^2 + EE*h*\[Nu]*w1 [x, y]*Derivative[1, 0][w1][x, y]^2))/(2*b^2*R*(-1 + \[Nu]^2)) + (q[1]^3*((-EE)*h*Derivative[0, 1][w1][x, y]^4 - 2*EE*h*Derivative[0, 1][w1][x, y]^2*Derivative[1, 0][w1][x, y]^2 - EE*h*Derivative[1, 0][w1] [x, y]^4))/ (2*b^4*(-1 + \[Nu]^2)) + q[1]*((q[7]*((-EE)*h*Derivative[0, 1][v1] [x, y]*Derivative[0, 1][w1][x, y]^2 - EE*h*Derivative[0, 1][w1][x, y] *Derivative[1, 0][v1][x, y]* Derivative[1, 0][w1][x, y] + EE*h*\[Nu]*Derivative[0, 1][w1] [x, y]*Derivative[1, 0][v1][x, y]*Derivative[1, 0][w1][x, y] - EE*h*\[Nu]*Derivative[0, 1][v1][x, y]*Derivative[1, 0][w1][x, y] ^2))/(b^3*(-1 + \[Nu]^2)) + (q[4]*((-EE)*h*\[Nu]*Derivative[0, 1][w1][x, y]^2*Derivative[1, 0] [u1][x, y] - EE*h*Derivative[0, 1][u1][x, y]*Derivative[0, 1][w1][x, y] *Derivative[1, 0][w1][x, y] + EE*h*\[Nu]*Derivative[0, 1][u1][x, y]*Derivative[0, 1][w1][x, y] *Derivative[1, 0][w1][x, y] - EE*h*Derivative[1, 0][u1][x, y] *Derivative[1, 0][w1][x, y]^2))/ (b^3*(-1 + \[Nu]^2)) + (-12*b^4*EE*h*w1[x, y]^2 - EE*h^3*R^2*Derivative[0, 2][w1][x, y]^2 - 2*EE*h^3*R^2*Derivative[1, 1] [w1][x, y]^2 + 2*EE*h^3*R^2*\[Nu]*Derivative[1, 1][w1][x, y]^2 - 2*EE*h^3*R^2*\ [Nu]*Derivative[0, 2][w1][x, y]*Derivative[2, 0][w1][x, y] - EE*h^3*R^2*Derivative[2, 0][w1][x, y]^2)/ (12*b^4*R^2*(-1 + \[Nu]^2))) Thanks you