givcos.m

various matlab programs to slove various problems

function [c,s]=givcos(xi, xk)
if (xk==0), c=1; s=0; else,
   if abs(xk) > abs(xi)
      t=-xi/xk; 
      s=1/sqrt(1+t^2); 
      c=s*t;
   else
      t=-xk/xi; 
      c=1/sqrt(1+t^2); 
      s=c*t;
   end
end
return