How can plot  f := proc (x, y) options operator, arrow; sin(x)*cos(y) end proc

as surface and contour (contour is project on xy plan)

If w := proc (x, y) options operator, arrow; piecewise(y <= .5, -2*tanh*(y-.25), .5 < y, 2*tanh*(.75-y)) end proc

how can print w(x,y) as matrix x=0..10,y=0..10?

I need to calculate sum w2(x,y),

v2 := proc (x, y) options operator, arrow; sin(x)*cos(y) end proc;
u2 := proc (x, y) options operator, arrow; 3*sin(x)-cos(y) end proc;
w2 := proc (x, y) options operator, arrow; diff(v2(x, y), x)-(diff(u2(x, y), y)) end proc;
L1 := proc (x, y) option inline; abs(w2(x, y)) end proc; CodeTools:-Usage(evalhf(add(add(abs(w2(x, y)), x = 0 .. 10), y = 0 .. 10)));
Error, (in CodeTools:-Usage) unable to evaluate built-in function `diff` in evalhf

 but it is error , how  can be rewritten properly?

 

How can reduce the number of circle in this curve

f := proc (x) options operator, arrow; sin(x) end proc;

plot(f(x), x = 0 .. 2*Pi);

 

I need help me, i need find maximum value,this form is false LL := proc (x, y) option inline; abs(wr(x, y)-w3(x, y)) end proc; CodeTools:-Usage(evalhf(maximize(LL(DD*i, DD*j), i = 0 .. N, j = 0 .. N))); Error, (in CodeTools:-Usage) cannot handle unevaluated name `i` in evalhf