HP35s Revisited Bug # 14

[Tugdual]

Ok, I've got it.

31.32309 = -R*X/(-466.92696*Q-R)

So basically, the 35s is picking the last result instead of the second "RCL X" and we can assume that "-R*X/(X*Q-R)" is evaluated with the equivalent RPN (very flat RPN but the I believe it is by design to avoid the use of a stack):

Code:

RCL X
RCL Q
*
RCL R
-
1/x
RCL R
*
RCL X
*
CHS

Another fun test.
Enter the EQN:

Code:

-R*156.25/(X*1.77951304201-208.333333334)

First attempt, the 35s asks for R?, then X? and returns -466.92696
Now pay attention, execute the EQN a second time. The 35s will ask for R?... skip X? and returns 31.32309.

Extremely odd bug because it also depends on values. With X=156.1 there is no problem... I wonder if the calculator somehow forgets to acknowledge that the former calculation was completed. May be there is a carry over or a precision issue and it leaves the calculation in an incomplete state and the next one restarts from its last value.