请教MATLAB画函数图形

%结果自己看。clear;clc;[u1 t1]=meshgrid(linspace(0,2,100),linspace(0,20,100));x1=u1。*sin(t1);y1=u1。*cos(t1);z1=t1/4;figure;mesh(x1,y1,z1)[x2 y2]=meshgrid(linspace(0,3,100));z2=sin(x2。*y2);figure;mesh(x2,y2,z2)[u3 t3]=meshgrid(linspace(0,2*pi,100),linspace(0,2*pi,100));x3=sin(t3)。*(3+cos(u3));y3=cos(t3)。*(3+cos(u3));z3=sin(u3);figure;mesh(x3,y3,z3)