This kind of math expression "sin(+(1.2))" in a calculated question breaks Sakai

Steps to reproduce the issue:

1. Create a new assessment.

2. Add this calculated question to the assessment:

Question text: "{{x}} {a}"

Var {a} => values from 1 to 2

Formula {{x}} => "sin(+({a}))"

3. Try to save the question. This action breaks Sakai. You need to reload the page to continue.

The problem is in this line: "e.calculate()" from "org.sakaiproject.tool.assessment.util.SamigoExpressionParser.parse(String, int)" because the method "org.mariuszgromada.math.mxparser.Expression.calculate()" does not work when it tries to parse this kind of expression: "sin(+(1.2))".