Using the Equation Library on 50g

[Nigel (UK)]

(07-27-2022 11:11 AM)matalog Wrote:  

(07-27-2022 07:26 AM)Marco Polo Wrote:  If equations are correct, than wrong result came from wrong data ;-)

I have gotten different results from entering the same data, it seems.

I tried the same thing again later, and it ended up being positive. Upon calculatiing the solution the calculator flashed up something about Reversal on screen. I'm not sure what that was.

When I was getting the negative reault, I went through all of my variable inputs and none were negative, for that projectile motion example, so the result shouldn't have been negative.

For example, if you are solving for \(v\) given \(u\), \(a\), and \(s\), the equation \(v^2=u^2+2as\) will give both a negative and positive value for \(v\). Which one the solver returns will depend on the value already stored in \(v\); storing different values will start the search for the root from a different place, and may lead to a different answer.

This is only an example - I don't know what problem you are solving. But it isn't necessarily strange that a negative root is returned when all inputs are positive, nor that the same inputs lead to a different root on a different occasion.

Nigel (UK)