例2*x个2+3*x-5;g=x2x7 >> syms x 2*x个2+3”x5;g=x2+x7 h=ft h=3*x~2+4米x-12 例2:fc(x)g=Nm(2*x) syms X fcos(x): g=sin(2*x); fg+f*g ans cos(x)/sin(x)+cos(x)*sin(x)例1：f= 2*x^2+3*x-5; g= x^2+x-7; >> syms x >> f=2*x^2+3*x-5; g= x^2+x-7; >> h=f+g h = 3*x^2+4*x-12 例2：f=cos(x);g= sin(2*x); >> syms x >> f=cos(x);g=sin(2*x); >> f/g+f*g ans = cos(x)/sin(x)+cos(x)*sin(x)