11-20-2015, 04:57 PM
Post: #1
 pwarmuth Junior Member Posts: 35 Joined: Sep 2015
2^(-x) == 1/(2^x) is returning 0. Any idea why?
11-20-2015, 05:08 PM
Post: #2
 Helge Gabert Senior Member Posts: 464 Joined: Dec 2013
RE: Logic test returning unexpected answer
Not surprising, because == doesn't do any and all simplifications for you.

Try (x-1)*(x+1) == x^2-1 also returns 0.

But x^2-1 == x^2-1 returns 1.
11-20-2015, 05:31 PM (This post was last modified: 11-20-2015 05:38 PM by pwarmuth.)
Post: #3
 pwarmuth Junior Member Posts: 35 Joined: Sep 2015
RE: Logic test returning unexpected answer
Ok, that makes sense.

Speaking of simplifications, I encountered this today as well.

Those two statements should be mathematically identical, but yet their simplifications are not the same. I know for certain the second one is correct.

Though if I add in an explicit multiply, it behaves.

11-20-2015, 06:17 PM
Post: #4
 Helge Gabert Senior Member Posts: 464 Joined: Dec 2013
RE: Logic test returning unexpected answer
Yes, don't skimp on the '*'!
11-20-2015, 10:05 PM
Post: #5
 Fortin Member Posts: 59 Joined: Jul 2015
RE: Logic test returning unexpected answer
Using the method, simplify(f-g)==0, works pretty well - where f ang g are the two items being compared.

For example: simplify(2^(-x) - 1/(2^x))==0
11-20-2015, 10:42 PM (This post was last modified: 11-21-2015 01:23 PM by Fortin.)
Post: #6
 Fortin Member Posts: 59 Joined: Jul 2015
RE: Logic test returning unexpected answer
(11-20-2015 05:31 PM)pwarmuth Wrote:  Ok, that makes sense.

Speaking of simplifications, I encountered this today as well.

Those two statements should be mathematically identical, but yet their simplifications are not the same. I know for certain the second one is correct.

Though if I add in an explicit multiply, it behaves.

This is because the intended implied multiplication involving 1/4 is calling 'of' instead of '*'.
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