Leticia-maria / SimpleSolver.jl

Easy interface for solving equations

SimpleSolver

This module provides an easy way to solve equations in a single real variable. It relies on NLsolve.

Solving equations using simple_solve

The function simple_solve is used to solve equations of the form f(x) = 0. The simplest form is simple_solve(f,x0) where x0 is an initial guess for the solution.

julia> simple_solve(cos,1)
1.570796326795489

julia> cos(ans)
-5.923537736000261e-13

Efficiency is gained by providing the derivative df of f by calling simple_solve(f,df,x0).

julia> f(x) = x^2-2;

julia> df(x) = 2x;

julia> simple_solve(f,df,1)
1.4142135623746899

julia> ans^2
2.0000000000045106

Problems

An initial value x0 where the derivative of the function is zero can cause trouble.

julia> simple_solve(cos,0)
NaN

Likewise, trouble ensues if the equation has no solution.

julia> f(x) = x^2 + 1;

julia> simple_solve(f,1)
NaN

Bisection method