Question about "True" or "False" answers on the Nspire CAS

[JB]

Hi,  my students were doing an intro to calculus lab for teh chain rule where they enter in their "educated guess" of the rule and it tells them true or false.  Would anyone know why sometimes it says false, and otehr times it would just show an equation that is not ture instead?  I have attached a screenshot as a sample of what it is doing below.

 

 

[JB]

sorry, typo...in too big of a hurry!  .It should read "other", not otehr",  "the" instead of "teh" and  "true", not "ture" at the end!  

[John Hanna]

 

 

Hi, JB,

 

In your screenshot below, the first expression simplifies to 5=3, hence ‘false’.

 

The others evaluate to an expression involving x, so there is no ‘true’ or ‘false’ because it depends on the value of x.

 

     John Hanna

     jeh...@optonline.net

     www.johnhanna.us

     T³ - Teachers Teaching with Technology

     "the future isn't what it used to be."

 

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[Jim Fullerenex]

Hi,

There is a quick remedy, given that you define "true" when two expressions are algebraically equivalent for all x.

when(f1(x) = f2(x), true, false, false)

Sent from my iPad

On 2012-3-7, at 23:55, JB <arcs...@cinci.rr.com> wrote:

Hi,  my students were doing an intro to calculus lab for teh chain rule where they enter in their "educated guess" of the rule and it tells them true or false.  Would anyone know why sometimes it says false, and otehr times it would just show an equation that is not ture instead?  I have attached a screenshot as a sample of what it is doing below.

 

 

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