# EquationProblem

System of nonlinear equations

## Description

Specify a system of equations using optimization variables, and solve the system
using `solve`

.

**Tip**

For the full workflow, see Problem-Based Workflow for Solving Equations.

## Creation

Create an `EquationProblem`

object by using the `eqnproblem`

function. Add equations to the problem by creating `OptimizationEquality`

objects and setting them as `Equations`

properties of the
`EquationProblem`

object.

```
prob = eqnproblem;
x = optimvar('x');
eqn = x^5 - x^4 + 3*x == 1/2;
prob.Equations.eqn = eqn;
```

**Warning**

The problem-based approach does not support complex values in the following: an objective function, nonlinear equalities, and nonlinear inequalities. If a function calculation has a complex value, even as an intermediate value, the final result might be incorrect.

## Properties

## Object Functions

`evaluate` | Evaluate optimization expression or objectives and constraints in problem |

`issatisfied` | Constraint satisfaction of an optimization problem at a set of points |

`optimoptions` | Create optimization options |

`prob2struct` | Convert optimization problem or equation problem to solver form |

`show` | Display information about optimization object |

`solve` | Solve optimization problem or equation problem |

`solvers` | Determine default and valid solvers for optimization problem or equation problem |

`varindex` | Map problem variables to solver-based variable index |

`write` | Save optimization object description |

## Examples

## Version History

**Introduced in R2019b**