Defining a function from $\mathbb {R}$^p to $\mathbb {R}$^q

For example:

• To define the function h  :  (x, y) $\rightarrow$ (x*cos(y), x*sin(y)).
  Input :
  h(x,y):=(x*cos(y),x*sin(y))
  Output :
  expr(" (x,y)->{
  x*cos(y),x*sin(y);
  }",0)
• To define the function h  :  (x, y) $\rightarrow$ [x*cos(y), x*sin(y)].
  Input :
  h(x,y):=[x*cos(y),x*sin(y)];
  Or :
  h:=(x,y)->[x*cos(y),x*sin(y)];
  Or :
  h(x,y):={[x*cos(y),x*sin(y)]};
  Or :
  h:=(x,y)->return[x*cos(y),x*sin(y)];
  Or :
  h(x,y):={return [x*cos(y),x*sin(y)];}
  Output :
  (x,y)->{return([x*cos(y),x*sin(y)]);}

Warning !!! the expression after -> is not evaluated.