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+--- Thread: Logic test returning unexpected answer (/thread-5166.html)
Logic test returning unexpected answer - pwarmuth - 11-20-2015 04:57 PM
2^(-x) == 1/(2^x) is returning 0. Any idea why?
RE: Logic test returning unexpected answer - Helge Gabert - 11-20-2015 05:08 PM
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.
RE: Logic test returning unexpected answer - pwarmuth - 11-20-2015 05:31 PM
Ok, that makes sense.
Speaking of simplifications, I encountered this today as well.
[attachment=2830]
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.
[attachment=2832]
RE: Logic test returning unexpected answer - Helge Gabert - 11-20-2015 06:17 PM
Yes, don't skimp on the '*'!
RE: Logic test returning unexpected answer - Fortin - 11-20-2015 10:05 PM
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
RE: Logic test returning unexpected answer - Fortin - 11-20-2015 10:42 PM
(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 '*'.