% Rules %trig1:={sin(~x)^2+cos(~x)^2=>1, cos(~x)^2+sin(~x)^2=>1}; trig1:={sin(~x)^2=>(1-cos(x)^2)}; let trig1; trig2:={tan (~x)=>(sin (x)/cos (x))}; let trig2; end;