Function cot

pub fn cot(func: Function) -> Function

Creates a Function equal to the cotangent of the passed Function

i.e f(x) ⟹ cot(f(x))

Example:

    let x = Function::default();
    let cot_of_x = cot(x);
    assert_eq!(cot_of_x.call(PI/2.), 0.);