[Maxima-discuss] Determining Real Part

[Thomas D. D. <to...@wa...>]

I am back at Swokowski, again.

kill(all);
p_val:40;  /* dynes/cm^2 */
dp_val:3;  /* dynes/cm^2/second */
v_val:60;  /* cm^3 */
assume(p(t)>0);
soln_c:solve(p_val*v_val^(14/10)=c,c);
eqn:p(t)*v(t)^(14/10)=rhs(first(soln_c));
soln_vt:solve(eqn,v(t))

I want to extract the real solutions in soln_vt.  I tried isreal_p(), 
realpart(), etc.  Is there a way?

There seems to be only one real part, the last in the solution set.

define(v(t),rhs(last(soln_vt)));
define(dv(t),diff(v(t),t));
subs:[diff(p(t),t)=dp_val,p(t)=p_val];
dv:subst(subs,dv(t));

I tried:

for s in solve(eqn,v(t)) do (
   tmp:rhs(s),
   print(s,realpart(tmp))
   )$

Tom Dean