MATLAB解微分方程

Uc=0.9292；
 Ac=3.8513e-004；
 Tc=0.8237；
 Cc=0.9843；
 y0=0.9486；
 f=inline('Tc*(-y+Cc*((Uc-Ac/(y.^2)).^0.5)','Tc','Cc','Uc','Ac','x','y');%微分方程的右边项
 dx=0.004; %x方向步长
xleft=0.029000;   %区域的左边界
xright=1.020991;  %区域的右边界
xx=xleft:dx:xright; %一系列离散的点
n=length(xx); %点的个数
%%(2)龙格--库塔法
RK=y0;
for i=2:n
 k1=f(Tc,Cc,Uc,Ac,xx(i-1),RK(i-1));
 k2=f(Tc,Cc,Uc,Ac,xx(i-1)+dx/2,RK(i-1)+k1*dx/2);
 k3=f(Tc,Cc,Uc,Ac,xx(i-1)+dx/2,RK(i-1)+k2*dx/2);
 k4=f(Tc,Cc,Uc,Ac,xx(i-1)+dx,RK(i-1)+k3*dx);
 RK(i)=RK(i-1)+dx*(k1+2*k2+2*k3+k4)/6;
end
运行后老是提示错误为
??? Error using ==> inlineeval
Error in inline expression ==> Tc*(-y+Cc*((Uc-Ac/(y.^2)).^0.5)
??? Error: Incomplete or misformed expression or statement.

Error in ==> inline.subsref at 25
    INLINE_OUT_ = inlineeval(INLINE_INPUTS_, INLINE_OBJ_.inputExpr, INLINE_OBJ_.expr);

Error in ==> gyddj2 at 69
 k1=f(Tc,Cc,Uc,Ac,xx(i-1),RK(i-1));
         请高手指点，谢谢！