# Is wxMaxima being lazy?

• Jul 24th 2010, 02:39 PM
rainer
Is wxMaxima being lazy?
Hello,

I recently downloaded the free CAS wxMaxima. I'm really, really pleased with it. I was expecting to have to pay some serious cash for this kind of computing power.

There is one small thing I don't quite get though. When I input a "solve for x" command involving an x under a square root, the output usually stops at the square root, treating it as though it were a different variable. This results in x remaining on both sides of the equation.

For example, when I want to solve for x in an equation such as the following...

$\sqrt{xy}=\frac{x+y}{2}$

[input: "solve(sqrt(x*y)=(x+y)/2,x);" ]

Instead of squaring both sides and then solving for x in a quadratic equation, wxMaxima gives me...

$x=2\sqrt{xy}-y$

Does anyone know of a way to get wxMaxima to *really* solve for x? With such a great program I imagine there must be and I am just unaware of it.

Thanks
• Jul 25th 2010, 11:37 AM
CaptainBlack
Quote:

Originally Posted by rainer
Hello,

I recently downloaded the free CAS wxMaxima. I'm really, really pleased with it. I was expecting to have to pay some serious cash for this kind of computing power.

There is one small thing I don't quite get though. When I input a "solve for x" command involving an x under a square root, the output usually stops at the square root, treating it as though it were a different variable. This results in x remaining on both sides of the equation.

For example, when I want to solve for x in an equation such as the following...

$\sqrt{xy}=\frac{x+y}{2}$

[input: "solve(sqrt(x*y)=(x+y)/2,x);" ]

Instead of squaring both sides and then solving for x in a quadratic equation, wxMaxima gives me...

$x=2\sqrt{xy}-y$

Does anyone know of a way to get wxMaxima to *really* solve for x? With such a great program I imagine there must be and I am just unaware of it.

Thanks

It is probably because it does not know that you are assuming both x and y are real, try to_poly_solve

CB
• Jul 27th 2010, 02:26 PM
rainer
Nope, that didn't help.