solve (-(w^2)*m*l^2 +m*l*g+k*d^2)*(-4*(w^2)*m*l^2 +2*m*l*g+2*k*d^2)*(-(1/4)*(w^2)*m*l^2 +(1/2)*m*l*g+k*d^2) - ((k^2)*(d^4)*((-(w^2)*m*l^2 +m*l*g+k*d^2)+(-(1/4)*(w^2)*m*l^2 +(1/2)*m*l*g+k*d^2)) for w