50g Multiple equation Solver (MES)

[Claudio L.]

(09-28-2017 03:21 PM)LGVE Wrote:  I was reading about MES in the HP 50g User's Guide and tried the example of solving triangles ( page 7- 9) on my calculator. It worked fine but when I tried to solve a triangle problem, one of the sides was negative. The data:
a=20
alpha=45 degrees
betha=60 degrees

I press White key with left arrow and ALL
I press Orange key with right arrow and ALL

The calculator gives as answers:
phi=75 degrees
b=24.49
c=-7.32

c must be positive.

Any suggestions?

Thanks in advance

Luis

The last value is comuputed probably from the cosine's law
C^2=A^2+B^2-2*A*B*cos(gamma)

Being quadratic, the solver might converge to either of the roots, with no easy way to persuade it to go the other way. One way is to provide initial guesses for A,B,C in the positive region (like 10). It might help it stay on the positive side but there's no guarantee.

So try again by setting B=10,C=10 as initial data, then solve for them too.