Solving Algebraic and Transcendental Equations: An Example

As an example of an algebraic equation, consider the equation f(u) = 0 for

This equation has a single real-valued root at u = 1.

1	In the Model Builder, click the Global Equations node in a Global ODEs and DAEs interface.

2	In the Settings window for Global Equations, enter u in the Name column and u^3+u-2 in the f(u,ut,utt,t) column (both entries on the same row).

3	Solve this using a stationary solver.

4	In the Settings window for State variable u (Global Evaluation), click the Evaluate button (), and the value of the root displays in the Table window.

As an example of a transcendental equation, consider the equation f(u) = 0 for

A root to this equation is approximately 0.56714. To enter it for the node:

1	In the Model Builder, click the Global Equations node.

2	Enter u in the Name column and exp(-u)-u in the f(u,ut,utt,t) column (both entries on the same row).

3	Compute the solution.

4	In the Settings window for State variable u (Global Evaluation), click the Evaluate button (), and the value of the root (rounded to 0.56714) displays in the Table window.

Derived Values and Tables