Re: Mathematica 6.01 does not know one can not divide by 0??

• To: mathgroup at smc.vnet.net
• Subject: [mg107206] Re: [mg107140] Mathematica 6.01 does not know one can not divide by 0??
• From: "David Park" <djmpark at comcast.net>
• Date: Fri, 5 Feb 2010 03:24:30 -0500 (EST)
• References: <20935297.1265283020598.JavaMail.root@n11>

```It's just the old "divide by zero" trap. I think that Mathematica subtracts
the rhs from the lhs and eliminates the offending terms right off.

eqn = 3 x + 1/(x - 5) == 15 + 1/(x - 5);
Solve[eqn]
{{x -> 5}}

Strictly speaking, Mathematica is correct because:

Limit[#, x -> 5] & /@ eqn
True

But I might learn otherwise.

David Park
djmpark at comcast.net
http://home.comcast.net/~djmpark/

From: zeno [mailto:zeno333 at mindspring.com]

I had Mathematica 6.01 try and solve this " equation", and it gives an
answer back of 5, which if substituted back into the equation, one
would be dividing by 0. Code and result here...

NSolve[3*x + (1/(x - 5)) == 15 + (1/(x - 5)), x]
{{x -> 5.}}

```

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