ASKSAGE: Sage Q&A Forum - Individual question feedhttp://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Mon, 17 Oct 2016 06:55:08 -0500What's this result of equation solving?http://ask.sagemath.org/question/35167/whats-this-result-of-equation-solving/Hi guys
I want to solve an equation that get from determinant of a matrix, but I cannot understand the result! Can anyone help me?
It's my code:
x = var('x')
A = Matrix([[0,1],[1,0]])
A = (I*x*A).exp()
A = A.determinant()
solve(A == 1,x,to_poly_solve ='force')
This is result!!!!!:
[x == 1/2*I*lambert_w(68)]
What is exactly that c68 (it's change every time!) [The result for equation should be pi/2]Sun, 16 Oct 2016 22:46:38 -0500http://ask.sagemath.org/question/35167/whats-this-result-of-equation-solving/Answer by eric_g for <p>Hi guys</p>
<p>I want to solve an equation that get from determinant of a matrix, but I cannot understand the result! Can anyone help me?</p>
<p>It's my code:</p>
<pre><code>x = var('x')
A = Matrix([[0,1],[1,0]])
A = (I*x*A).exp()
A = A.determinant()
solve(A == 1,x,to_poly_solve ='force')
</code></pre>
<p>This is result!!!!!:</p>
<pre><code>[x == 1/2*I*lambert_w(68)]
</code></pre>
<p>What is exactly that c68 (it's change every time!) [The result for equation should be pi/2]</p>
http://ask.sagemath.org/question/35167/whats-this-result-of-equation-solving/?answer=35169#post-id-35169`c68` stands for an arbitrary constant. That's because there is an infinite number of solutions to your equation, not only pi/2, since A is actually equal to 1, as you can see by expanding it:
sage: A.expand()
1
NB: you may also use `A.simplify_full()`, which yields the same result (A=1).Mon, 17 Oct 2016 06:55:08 -0500http://ask.sagemath.org/question/35167/whats-this-result-of-equation-solving/?answer=35169#post-id-35169