1.定义一组Symbolic Variable 2.解方程 a.solve() clc; clear; syms x; solve('(cos(x))^2-(sin(x))^2',x) ans = pi/4 clc; clear; syms x; y=(cos(x))^2+(sin(x))^2; solve(y,x) ans = Empty sym: 0-by-1 解多项式 解含参数的式子 clc; clear; syms x y a b r; solve('(x-a)^2+(y-b)^2-r^2') a