Should CAS solve
sqrt(y)=x
for y by giving solution as y=x^2 without saying this is valid only for x>=0 ?
Only Maxima would ask the user if x was negative,positive or zero when solving this equation.
Maple:
=======
eq:=sqrt(y)=x;
PDEtools:-Solve(eq,y);
y = x^2
Mathematica:
=============
eq = Sqrt[y] == x;
Solve[eq, y]
{{y -> x^2}}
Maxima
=======
(%i1) solve(sqrt(y)=x,y)
Is x positive, negative or zero?
positive
2
(%o1) [y = x ]
Fricas
========
solve(sqrt(y)=x,y)
2
(4) [y = x ]
At school, if I wrote in the exam that the solution of
sqrt(y)=x is y=x^2 without saying this is for x>=0, the
teacher will take one or more point off.
Why do then most CAS systems get away with it then? Is this just by convention
then?
--Nasser
Should CAS solve
sqrt(y)=x
for y by giving solution as y=x^2 without saying this is valid only for x>=0 ?
Only Maxima would ask the user if x was negative,positive or zero when solving this equation.
Maple:
=======
eq:=sqrt(y)=x;
PDEtools:-Solve(eq,y);
y = x^2
Mathematica:
=============
eq = Sqrt[y] == x;
Solve[eq, y]
{{y -> x^2}}
Maxima
=======
(%i1) solve(sqrt(y)=x,y)
Is x positive, negative or zero?
positive
2
(%o1) [y = x ]
Fricas
========
solve(sqrt(y)=x,y)
2
(4) [y = x ]
At school, if I wrote in the exam that the solution of
sqrt(y)=x is y=x^2 without saying this is for x>=0, the
teacher will take one or more point off.
Why do then most CAS systems get away with it then? Is this just by convention
then?
--Nasser
On Monday, January 11, 2021 at 1:33:07 PM UTC-10, Nasser M. Abbasi wrote:
Should CAS solve
sqrt(y)=x
for y by giving solution as y=x^2 without saying this is valid only
for x>=0 ?
Only Maxima would ask the user if x was negative,positive or zero
when solving this equation.
Maple:
=======
eq:=sqrt(y)=x;
PDEtools:-Solve(eq,y);
y = x^2
Mathematica:
=============
eq = Sqrt[y] == x;
Solve[eq, y]
{{y -> x^2}}
Maxima
=======
(%i1) solve(sqrt(y)=x,y)
Is x positive, negative or zero?
positive
2
(%o1) [y = x ]
Fricas
========
solve(sqrt(y)=x,y)
2
(4) [y = x ]
At school, if I wrote in the exam that the solution of
sqrt(y)=x is y=x^2 without saying this is for x>=0, the
teacher will take one or more point off.
Why do then most CAS systems get away with it then? Is this just by convention then?
Derive 6.10 returns y = if(x>0, x^2)
Should CAS solve
sqrt(y)=x
for y by giving solution as y=x^2 without saying this is valid only for x>=0 ?
Only Maxima would ask the user if x was negative,positive or zero when solving this equation.
Maple:
=======
eq:=sqrt(y)=x;
PDEtools:-Solve(eq,y);
y = x^2
Mathematica:
=============
eq = Sqrt[y] == x;
Solve[eq, y]
{{y -> x^2}}
Maxima
=======
(%i1) solve(sqrt(y)=x,y)
Is x positive, negative or zero?
positive
2
(%o1) [y = x ]
Fricas
========
solve(sqrt(y)=x,y)
2
(4) [y = x ]
At school, if I wrote in the exam that the solution of
sqrt(y)=x is y=x^2 without saying this is for x>=0, the
teacher will take one or more point off.
Why do then most CAS systems get away with it then? Is this just by convention
then?
Sysop: | Keyop |
---|---|
Location: | Huddersfield, West Yorkshire, UK |
Users: | 113 |
Nodes: | 8 (1 / 7) |
Uptime: | 51:34:05 |
Calls: | 2,470 |
Calls today: | 1 |
Files: | 8,638 |
Messages: | 1,897,184 |