Re: why is this happening?

• To: mathgroup at smc.vnet.net
• Subject: [mg99243] Re: why is this happening?
• From: dh <dh at metrohm.com>
• Date: Thu, 30 Apr 2009 06:26:29 -0400 (EDT)
• References: <gt9aq0\$q7o\$1@smc.vnet.net>

Hi,

the second equation is NOT a scaled form of the first one, but a

different.  Perhaps you mean:

ld + k2 + ld^2/k1 == 0

Daniel

sean_incali at yahoo.com wrote:

> Consider the following.

>

> Solve[k1 ld + k1 k2 + ld^2 == 0, ld]

>

> vs

>

> Solve[k2/k1 + ld^2 + ld == 0, ld]

>

>

> I expected to get the output I got from the first code.

>

>>From the second code, I was expecting something along the lines of

>

> ld ->-1 + (SquareRoot[1 - 4 (k2/k21)])/2

> ld -> -1 - (SquareRoot[1 - 4 (k2/k21)])/2

>

> since that is the answer.

>

> Why is Mathematica turning the second scaled equation into the

> unscaled one in the first before solving it?

>

> Thanks for any insight.

>

> Sean

>

>

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