The 4 most common syntax mistakes encountered by users are:

**Copy-Paste**(symbols like**μ**) from text/pdf/websites. You can**only**copy-paste LaTeX-code (e.g. \mu), otherwise your answer can't be interpreted.**Incomplete math:**for example a fraction without numerator and/or denominator, or a function without argument.**"to the Power" twice:**having two "to the Power" (i.e. ^ in LaTeX) in a row without an argument in between (e.g. the syntax of x^^2 is wrong).**Correct LaTeX:**make sure you use the math insert menu or type LaTeX directly to create proper syntax.

If you insert an answer with incorrect syntax, you will get a warning about this. In case this happens this will **not** count as an attempt and thus you won't lose points.

To read in more detail about syntax in Grasple, see the sections below.

# Answers and feedback

Grasple's answer box is also a calculator, so the answer 1 will also be accepted as 8/8, cos(0) or √1. When your answer is correct, you will see a green box.

When you answer incorrectly, you can retry. After three retries, you will be shown the correct answer, often accompanied by an explanation of how to solve your question. For questions with multiple sub questions, the explanation will generally be shown after the final sub question has been tried.

# Syntax

You can either use the drop down menu above the answer box to find symbols (e.g. √), or you can type LaTeX directly followed by a space (e.g. \sqrt followed by space for √). There are three letters that have special use in Grasple:

The letter *I *and *i *(uppercase and lowercase) are used to denote the imaginary number (e.g. √−1=I).

The letter e is used to denote Euler's number (e.g. ln(e)=1).

The letter π is used to denote pi (e.g. cos(π)=−1).

Use a period . to indicate a decimal point (e.g. 3.14).

Finally, when writing fractions, do not use the mixed fraction notation to simplify the fraction. Meaning that if you want to write 1.5, write it as 3/2 instead of 1 1/2, as 1 1/2 will be read as 1·1/2=1/2.

# Warning: copy-paste from text

Do not copy-paste symbols from the exercises, text or other resources. Probably the symbols won't be recognized and thus your answer will be marked as incorrect. To fill in an answer use LaTeX or the buttons in the menu around the answer box.

# Sets and intervals specific

Grasple will not recognize expressions with sets being represented as variables (e.g. "A U B" instead of "{1,2} U {3,4}") as a submittable answer to an exercise, meaning that a syntax error will be raised. To prevent that, specify well defined sets for an answer to an exercise. In the example below, the first syntax raised an error, while the second one is accepted.

# Linear Algebra specific

For linear algebra questions all the above holds, but there are some additional functionalities which will be explained in the next section.

## Vector and Matrix

To insert a matrix or a vector, use the menu at the bottom right of the answer box. The size of the matrix you indicate by selecting a number of squares depicts the size of the matrix. See an example below:

**Fractions and numeric values**

Always give exact values as entries within a matrix or vector. So, do **not **type 0.3333 but type 1/3. Other examples:

Do

**not**type 1.4142, but use √2Do not type 3.14, but use π

## Exercises with Basis as answer

Some exercises require you to give a basis. When you get to those exercises, you can give a basis by enclosing a list of vectors, separated by comma's ( **,** ), between curly brackets: **{ }**. See an example below:

Do you have questions or feedback about the syntax? Ask us via the chat in the bottom right corner!