reserve q,th,r for Real,
  a,b,p for Real,
  w,z for Complex,
  k,l,m,n,n1,n2 for Nat,
  seq,seq1,seq2,cq1 for Complex_Sequence,
  rseq,rseq1,rseq2 for Real_Sequence,
  rr for set,
  hy1 for 0-convergent non-zero Real_Sequence;
reserve d for Real;
reserve th,th1,th2 for Real;

theorem
  cos(PI/2) = 0 & sin(PI/2) = 1 & cos(PI) = -1 & sin(PI) = 0 &
  cos(PI+PI/2) = 0 & sin(PI+PI/2) = -1 &
  cos(2 * PI) = 1 & sin(2 * PI) =0 by Th75;
