matlab符号推导求解复杂方程问题

yanzhenhua

请各位帮我看看如下程序为何没有显示解？方程比较长，其实并不复杂。

clear all;clc;syms k0 k1 k2 du2 r R d a u;dF=k1 - (k2*(a - d/2 + du2 - r + ((R + r)^2 - (u - ((R + r)^2 - (1/2*d - a + r)^2)^(1/2))^2)^(1/2)))/((R + r)^2 - (u - ((R + r)^2 - (1/2*d - a + r)^2)^(1/2))^2)^(1/2) + (k2*(u - ((R + r)^2 - (1/2*d - a + r)^2)^(1/2))*(2*u - 2*((R + r)^2 - (1/2*d - a + r)^2)^(1/2)))/(2*((R + r)^2 - (u - ((R + r)^2 - (1/2*d - a + r)^2)^(1/2))^2)) - (k2*(u - ((R + r)^2 - (1/2*d - a + r)^2)^(1/2))*(2*u - 2*((R + r)^2 - (1/2*d - a + r)^2)^(1/2))*(a - d/2 + du2 - r + ((R + r)^2 - (u - ((R + r)^2 - (1/2*d - a + r)^2)^(1/2))^2)^(1/2)))/(2*((R + r)^2 - (u - ((R + r)^2 - (1/2*d - a + r)^2)^(1/2))^2)^(3/2));eq=dF-k0;S=solve(eq,u);disp(S)