Non solution for 2 equations with 2 variables

[jtamezga]

Lets gonna suppose you want to solve 2 equations (non linear) with 2 variable using the SOLVE app.

The objective is define the sample size and maximum of non conforming product permited (desig of a sampling plan). Then I need to use the probability function BINOMIAL.

So the system of equations are:

0.95=BINOMIAL_CDF(X,0.015,Y)
0.10=BINOMIAL_CDF(X,0.045,Y)

The practical and correct answer is X=260 and Y=7

For this kind of system X and Y are integers and positive using minitab but using other kind of computational solver this 2 variables can result real and positive ... its ok, no problem.

The problem is, if you use the SOLVE app, you can't get the answer, and after a minute, sometimes, the calculator can crash ... you can use initial values like 0, 1, 0.5 and 100, but never get the correct answer.

Please, help!

[roadrunner]

I think the solve app uses either bisection or newton's method. Both require continuity about the point of solution. BINOMIAL_CDF() is not.

Don't know why you experienced a crash. My emulator just didn't give an answer. Are you running the latest version?

-road