Using EQN, I have entered two equations:(X+2)*(X2)
and
X^24
Next, I input
3 STO X
EQN (then 'select' (X+2)*(X2))
SOLVE X
And the output is X=2.0000I repeat the process with X^24 and get the same result.
Now, I input
3 STO X
and repeat the above steps.
For (X+2)*(X2) I get the result X=2.0000 as expected.
But for X^24 I get X=2.0000.
I cannot seem to obtain X=2.0000 as a root of X^24.Why is this?
Question about SOLVE on hp 35s


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08042007, 07:30 AM
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08042007, 07:36 AM
Same behavior of the HP33s. Look in the Forum.  Antonio ▼
08042007, 08:35 AM
Thanks. ▼
08042007, 09:35 AM
See example 2 in the 35s learning module "Formula solver part 2" found here:
Example 2 suggests the workaround.
08042007, 09:20 AM
Tried your equation / SOLVE at HP15C, which gives X= 2.0000 and X= 2.0000. Maybe the correct answer of HP35s is found in another register...
Edited: 4 Aug 2007, 10:21 a.m.
08042007, 12:53 PM
Matt  Here's the link to the thread in the Forum Archives: http://www.hpmuseum.org/cgisys/cgiwrap/hpmuseum/archv014.cgi?read=62665#62665 The link is my proposed solution (obviously not adopted); scroll to the top to find a very similar discussion for the HP33S. It turns out that the "direct solution" logioc seems to have been lifted from the HP17B/HP27S from 1988; I didn't know that at the time.  KS
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08042007, 01:02 PM
And, again, I am still sorry for the shortness of that title back then in my response to you. :) This "direct solve" approach is considered a feature. You don't take features away...anyone knows that. :) Short answer: if you have a polynomial that is missing a term, add the term with a 0 coefficient. X^24=0 would be entered as x^2+0x4=0. Then the solver will not try a direct solution. That is the way it is.
08052007, 06:14 AM
Thanks for the links. 