# Increasing the accuracy of residue in FindRoot

I have solved a system of non-linear equations with findRoot. I tried to avoid inexact coefficients and also assign a high working precision. This is my snippet:

rho0=1.0; rho1=1.0;rho2=10^(-5);rhoint=10^(0);lambdaD=210;

• You do use inexact numbers when you set rho0=1.0; rho1=1.0;. Better use rho0 = 1; rho1 = 1; instead. Then you may also use FindRoot[fr,[...]] instead of FindRoot[frprecise,[...]]. – Henrik Schumacher Mar 30 '19 at 20:17
• Your system of equations can be solved by Solve as well. If you use exact input (e.g., use rho0 = 1; rho1 = 1 as recommended by @Henrik), then you will get an exact answer that you can numericize to any desired precision. – Carl Woll Mar 30 '19 at 20:32