solve(), fsolve() differences on handheld versus emulator
02-26-2014, 04:02 PM
Post: #1
 CR Haeger Member Posts: 275 Joined: Dec 2013
solve(), fsolve() differences on handheld versus emulator
Hello,

I entered the following two functions into both the HHC and EMU using CAS:

f:=(x)->5000/(500*e^((-x)/4)+2);
g:=(x)->3*x²-10*x;

Then plotted them in Function App using f(X) and g(X) which worked great. These functions appear to have four intersections.

I returned to CAS to try to find the intersections f(x)=g(x) these using solve() and fsolve().

On the HHC
solve(f(x)=g(x),x) gives {-.7,5.7,21.9,27.4} // okay and shows as list
fsolve(f(x)=g(x),x) gives [-.7,5.7,21.9,27.4] // okay and shows as vector

On the EMU
solve(f(x)=g(x),x) gives []
fsolve(f(x)=g(x),x) gives []
solve(f(x)=g(x),x,-100..100) gives [-.7,5.7,21.9,27.4] // okay and shows as vector
fsolve(f(x)=g(x),x,-100..100) gives [-.7,5.7,21.9,27.4] // okay and shows as vector

In both HHC and EMU, CAS in approx mode with page 1,2 settings identical. Using latest version (5447) and CAS (1.1.0-27) on both.

A couple of questions:
1. Any idea why solve, fsolve acting differently on HHC vs EMU?
2. Any way to control the results as a {list} versus [vector]? I ask as the {list} output is handy if you want to use it in say f(x) where x={x val list} --> gives {y values list}

Best,
Carl
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