# convert(f,form) convert an expression f to a different form ;
# e.g. convert sin(x) to exp ;

convert(a_,arctrig):=toarctrig(a);
convert(a_,arctrigh):=toarctrigh(a);
convert(a_,binomial):=tobinomial(a);
convert(a_,degree):=todegree(a);
convert(a_,degrees):=todegree(a);
convert(a_,exp):=toexp(a);
convert(a_,factorial):=tofactorial(a);
convert(a_,float):=n(a);
convert(a_,gamma):=togamma(a);
convert(a_,hyperbolic):=totrigh(a);
convert(a_,int):=toint(a);
convert(a_,log):=tolog(a);
convert(a_,ln):=tolog(a);
convert(a_,radian):=toradian(a);
convert(a_,radians):=toradian(a);
convert(a_,sum):=tosum(a);
convert(a_,parfrac):=toparfrac(a);
convert(a_,polar):=topolar(a);
convert(a_,power):=topower(a);
convert(a_,trig):=totrig(a);
convert(a_,trigh):=totrigh(a);

#convert(a_+b_,form_):=convert(a,form)+convert(b,form);
#convert(a_*b_,form_):=if(isnumber(a), a*convert(b,form),convert(a,form)*convert(b,form));
#convert(a_*b_,form_):=convert(a,form)*convert(b,form);