matlab 多项式化简aa=4*R*n1*cos(a) + (4*R^2*n2*cos(a)*sin(a)*(sin(t)*(1 - (4*R^2*cos(a)^2*sin(a)^2)/(L - R)^2)^(1/2) + (2*R*cos(a)*sin(a)*sin(t))/(L - R)))/(L - R)

matlab 多项式化简aa=4*R*n1*cos(a) + (4*R^2*n2*cos(a)*sin(a)*(sin(t)*(1 - (4*R^2*cos(a)^2*sin(a)^2)/(L - R)^2)^(1/2) + (2*R*cos(a)*sin(a)*sin(t))/(L - R)))/(L - R)
matlab 多项式化简
aa=
4*R*n1*cos(a) + (4*R^2*n2*cos(a)*sin(a)*(sin(t)*(1 - (4*R^2*cos(a)^2*sin(a)^2)/(L - R)^2)^(1/2) + (2*R*cos(a)*sin(a)*sin(t))/(L - R)))/(L - R)

matlab 多项式化简aa=4*R*n1*cos(a) + (4*R^2*n2*cos(a)*sin(a)*(sin(t)*(1 - (4*R^2*cos(a)^2*sin(a)^2)/(L - R)^2)^(1/2) + (2*R*cos(a)*sin(a)*sin(t))/(L - R)))/(L - R)
直接simple（aa）或者simplify（aa）
ans =
4*R*n1*cos(a) + (4*R^2*n2*cos(a)*sin(a)*(sin(t)*(1 - (4*R^2*cos(a)^2*sin(a)^2)/(L - R)^2)^(1/2) + (2*R*cos(a)*sin(a)*sin(t))/(L - R)))/(L - R)
说明化简不了
再试试提公因式指令
rs=subexpr(aa,'w')
w =
L - R
rs =
4*R*n1*cos(a) + (4*R^2*n2*cos(a)*sin(a)*(sin(t)*(1 - (4*R^2*cos(a)^2*sin(a)^2)/w^2)^(1/2) + (2*R*cos(a)*sin(a)*sin(t))/w))/w