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Re: simplifying expressions

• To: mathgroup at smc.vnet.net
• Subject: [mg20208] Re: [mg20172] simplifying expressions
• From: BobHanlon at aol.com
• Date: Wed, 6 Oct 1999 21:06:27 -0400
• Sender: owner-wri-mathgroup at wolfram.com

Rip,

See online help for Rationalize.

expr1 = 6t^2 / (4t^2 + 9t^4)^(3/2);

expr2 = 6.t^2 / (4t^2 + 9t^4)^1.5;

Rationalize[expr1 - expr2]

0

Bob Hanlon

In a message dated 10/4/1999 1:42:15 AM, bitbucket at home.com writes:

>I'm sure this is an elementary question, and I apologize for that.
>
>I'm trying to learn Mathematica (3.0) by working my way thru a
>differential geometry text which uses it.
>
>I have worked out the curvature in two ways, for the curve (t^2,t^3,0).
>The answer is 6t^2 / speed^3, where speed = (4t^2 + 9t^4)^.5 .
>
>Unfortunately, one of the Mathematica answers has real numbers and the
>other has integers, and Mathematica doesn't get zero when I subtract
>one from the other.
>
>To be more specific, the two numerators are 6. t^2. and 6 t^2, and the
>denominators are 1.5 and 3/2
>
>How do I find out what's going on?
>