Ask Your Question

Wrong answer on inequality problem

asked 2015-10-17 18:15:53 +0100

leothan gravatar image

updated 2015-10-17 21:04:50 +0100

vdelecroix gravatar image

The problem I'm having is the solution I get on sage when solving the following inequality


It gives me the wrong answer

([x < -5], [x >= -1])

the answer should be


The answer can be checked at here at wolframalpha. I'm still new to sage and in the learning process I don't know if I might be doing something wrong.

edit retag flag offensive close merge delete

1 Answer

Sort by ยป oldest newest most voted

answered 2015-10-17 21:06:50 +0100

vdelecroix gravatar image

updated 2015-10-17 21:09:30 +0100

The problem seems to be that Sage makes sense of "+infinity > finite number" situations. Even in the following where both sides of the inequality are infinite

sage: A = (4*x+5)/(x^2)
sage: B = 4/(x+5)
sage: solve(A >= B, x)
[[x < -5], [x >= -1]]
sage: solve(A/x^2 >= B/x^2, x)
[[x < -5], [x >= -1]]


edit flag offensive delete link more

Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account.

Add Answer

Question Tools

1 follower


Asked: 2015-10-17 18:15:53 +0100

Seen: 191 times

Last updated: Oct 17 '15