solve normCdf

[Per F]

Why does the command

     solve(normCdf(x,...,100,10)=0.1,x)

not give any information about why it does not calculate.

The other two commands give the information that more solutions might exist.

See attached picture.

[Jim Fullerenex]

I met that problem too. I guess normCdf is using a faster algorithm instead of the definition formula of normal distribution, so in this sense the command isn't solvable.

Best,

Jim

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<solve normCdf.jpg>

[epi van winsen]

There are more strange effects when combining nsolve and normcdf.

See the screen where the equation  nSolve(normCdf(40.5,10^99,40,8/sqrt(n))=0.05,n) is solved.

Restricted domains for the variable to solve for seem to help. Giving startvalues don't.

The Error message is cryptic to me. Who knows what has to be numeric?

epi van winsen
evwi...@gmail.com

Everyone is a genius. 
But if you judge a fish on its ability
to climb a tree, it will live its whole 
life believing that it is stupid.
A. Einstein