HP Prime - Brain Teaser

[CR Haeger]

Thanks Eric for trying and your feedback.

I agree that the Quadratic and Geometry Apps are not helpful with this type of problem. I also agree that the Solver App is kind of a minefield to get equations into. So far, I found a couple of ways that relate to this problem:

* Create the variables (xt, yt, t, g, v0 etc) in CAS or Home using := or STO first. Then Solver App will let you enter the equations in E1, E2 as xt=v0*t... and yt=-1/2... From here, Num seems to let you solve numerically for variable(s).

** I preferred to first create equations in CAS (eq1, eq2) without first creating the variables. eq1:=xt=v0*COS(θm)*t... Then I assign Solve.E1:=eq1 and same for E2, eq2. Now when I use Solver App (Num view), it prompts me to create the new variables. After saying yes, it allows for numerical solving.

I prefer the second method as it seems to allow for other CAS work, like numeric fsolve() and algebraic solve().