List of variables and of expressions

The lvar command finds the variables and non-rational that make up an expression.

lvar takes expr, an expression.
lvar(expr) returns a list of variable names and non-rational expressions such that expr its argument is a rational function with respect to the variables and expressions of the list.

lvar(x*y*sin(x)^2)

⎡
⎣

x,y,sin x

⎤
⎦

lvar(x*y*sin(x)^2+ln(x)*cos(y))

⎡
⎣

x,y,sin x,ln x,cos y

⎤
⎦

lvar(y+x*sqrt(z)+y*sin(x))

⎡
⎢
⎣

y,x,

√

,sin x

⎤
⎥
⎦