How students enter algebraic expressions
In general, students can enter expressions in a format that is natural, with a slash (/) to indicate division or fractions, an asterisk (*) to indicate multiplication, parentheses for grouping, and a caret (^) to indicate exponentiation.
sin(2x^(y+z)) is interpreted as
sqrt((2H)/g) is interpreted as
Math palette for expression questions
Parsing and evaluation
Learning Catalytics uses R (The R Project for Statistical Computing) to parse and evaluate algebraic expressions that students enter in response to an expression question. In general, most syntax that is valid in R is also valid in Learning Catalytics. The main exception is that Learning Catalytics assumes that all variables are only one letter (with N and n considered different variables); this way, a student can enter 2xy and it is interpreted as 2*x*y. Students can also use common functions: sin, cos, tan, arccos, arcsin, arctan, log, ln, and sqrt.