BUILT-IN MATHEMATICA SYMBOL

NSolve

NSolve[expr, vars]
attempts to find numerical approximations to the solutions of the system expr of equations or inequalities for the variables vars.

NSolve[expr, vars, Reals]
finds solutions over the domain of real numbers.

Details and Options Details and Options

NSolve[{expr₁, expr₂, ...}, vars] is equivalent to NSolve[expr₁&&expr₂&&..., vars].
A single variable or a list of variables can be specified.
NSolve gives solutions in terms of rules of the form .
When there are several variables, the solution is given in terms of lists of rules: .
When there are several solutions, NSolve gives a list of them.
When a single variable is specified and a particular root of an equation has multiplicity greater than one, NSolve gives several copies of the corresponding solution.
NSolve[expr, vars] assumes by default that quantities appearing algebraically in inequalities are real, while all other quantities are complex.
In NSolve[expr, vars, Reals] all variables, parameters, constants, and function values are restricted to be real.
NSolve[expr&&varsReals, vars, Complexes] solves for real values of variables, but function values are allowed to be complex.
NSolve deals primarily with linear and polynomial equations.
The following options can be given:
Method Automatic what method should be used

WorkingPrecision Automatic precision to be used in computations
NSolve gives if there are no solutions to the equations.
NSolve gives if the set of solutions is full dimensional.