reserve p,q,r,th,th1 for Real;
reserve n for Nat;

theorem
  sinh.(p+r)=(sinh.p)*(cosh.r) + (cosh.p)*(sinh.r) & sinh.(p-r)=(sinh.p)
  *(cosh.r) - (cosh.p)*(sinh.r) by Lm3,Lm8;
