Advanced Search

Question: Basic question on solve and extra solutions

Question:Basic question on solve and extra solutions

nm 10219 Maple 2024
solve pdetools
March 20 2024
1

Maple gives solutions that do not satisfy the equation. Wondering what do I need to change.  

restart;
n:=3;m:=2;
eqx:=x^(n/m)=a;
maple_sol:=[PDEtools:-Solve(eqx,x)]; #also tried solve()
F:=map(X->eval(eqx,X),maple_sol);
map(X->evalb(X),F);

 

I always verified in Mathematica

Any thought what is going on and what do I need to change in my Maple code to make it give the solution x=a^(2/3) only?  

It is also possible that Mathematica is the one who is skipping the two complex solutions, but then I need to verify these in Maple, and so far I can't. Only the first solution is verified by Maple.

Even simplification with assuming a>0 do not verify these two extra solution given with complex values. I also tried RealDomain package but this also had no effect. I tired assuming real also and tried simplify with symbolic option.

Anything else I should try?

Maple 2024 on windows 10

update

As I said, I tried RealDomain but with PDEtools:-Solve. With solve it works. Is this a bug? worksheet below

35788

> 

restart;

35788

> 

interface(version);

`Standard Worksheet Interface, Maple 2024.0, Windows 10, March 01 2024 Build ID 1794891`

> 

Physics:-Version();

`The "Physics Updates" version in the MapleCloud is 1701. The version installed in this computer is 1693 created 2024, March 7, 17:27 hours Pacific Time, found in the directory C:\Users\Owner\maple\toolbox\2024\Physics Updates\lib\`

> 

restart;

35788

> 

n:=3;m:=2;
eqx:=x^(n/m)=a;
use RealDomain in (PDEtools:-Solve(eqx,x)) end use;
F:=map(X->eval(eqx,X),[%]);
map(X->evalb(X),F);

3

2

x^(3/2) = a

x = a^(2/3), x = (1/4)*a^(2/3)*(1+I*3^(1/2))^2, x = (1/4)*a^(2/3)*(I*3^(1/2)-1)^2

[a = a, (1/16)*4^(1/2)*(a^(2/3)*(1+I*3^(1/2))^2)^(3/2) = a, (1/16)*4^(1/2)*(a^(2/3)*(I*3^(1/2)-1)^2)^(3/2) = a]

[true, false, false]

> 

restart;

35788

> 

n:=3;m:=2;
eqx:=x^(n/m)=a;
use RealDomain in (solve(eqx,x)) end use;
F:=map(X->eval(eqx,x=X),[%]);
map(X->evalb(X),F);

3

2

x^(3/2) = a

a^(2/3)

[a = a]

[true]

 

 

Download real_domain_solve_vs_PDEtools_Solve.mw
Please Wait...