Grasple is unique in providing support for Linear Algebra.

In this guide you can find what is currently possible and what is not possible yet.

We will start by showing different questions and how you can enter those in Grasple.

The main things to keep in mind:

- You have to enter the correct answer
- There needs to be one unique solution to the question. If there are infinite possible solutions (ie: provide a basis), please contact support to see if we can support your case.

#### The answer is a matrix

Examples of questions that ask for a matrix include: providing the reduced echelon form of a given matrix, provide the inverse of matrix or perform some matrix calculation. The answer in this case is a* matrix*.

In Grasple, select the *Equation* question type, click the squares in the math-bar, and fill in the correct answer.

The answer given by the student will be compared with the correct answer as an *exact match**,*** **meaning that all the numbers have to be the same and in the same position in the matrix.

This means that if the correct answer contains pi, entering 3.1415 will not be correct.

#### The answer is a vector

We consider a vector to be a 1xn matrix, so this is the same as adding a matrix.

A column vector and row vector are two different answers. If you want both of them to be marked as correct, provide both of them as correct answer by adding multiple correct answers. Learn how to add additional answers here.

**The answer is a number**

When a question asks for say the determinant of a matrix, the answer is simply one *number*.

Depending on the question, you can use the Number or Equation type.

- Use Number in case you want to allow numeric approximations. (ie: 2.892)
- Use Equation in case the number has to be exact (ie: 3/4 would be correct and 0.749 would not be correct)

Note: please pay attention to how you ask a question here. Instead of saying: provide all the eigenvalues and corresponding eigenvectors, ask: please give a eigenvector and then enter all the eigenvalues as additional correct answers. Learn how to add additional answers here.

You can also add subquestions, meaning that you can first ask the learner to provide one of the eigenvalues and then one of the eigenvectors.

What is **not possible** for now is linking the subquestions, ie: provide one of the eigenvalues and then only marking correct the *corresponding* eigenvalue.

#### Advanced checks (basis, solution to a system of equations and vector direction)

Currently there are 3 advanced advanced checks available for Linear Algebra exercises. Read below (by clicking on the links) how to use each of the advanced checks in your own exercises.

- provide a basis
- provide a solution to an indeterminate system of equations
- check the whether the answer is parallel to a vector

We are working on providing more advanced checks for Linear Algebra. Please contact support if you have exercises which you would like to create, but which require additional advanced checks.

If you have any doubts or questions, do not hesitate to contact us using the chat icon on the bottom right of this screen.

Thank you for entering exercises so people can practice and learn Linear Algebra!