### 4.4.1 `fsolve` or `nSolve` with the option `bisection_solver`

This algorithm of dichotomy is the simplest but also generically
the slowest.
It encloses the zero of a function on an interval.
Each iteration, cuts the interval into two parts. We compute the middle point
value. The function sign at this point, gives us the half-interval
on which the next iteration will be performed.

Input :

`fsolve((cos(x))=x,x,-1.. 1,bisection_solver)`

Output :

`[0.739085078239,0.739085137844]`