Function number_diff::acos

pub fn acos(func: Function) -> Function

Creates a Function equal to the arccosine of the passed Function

i.e f(x) ⟹ acos(f(x))

Example:

    let x = function::default();
    let acos_of_x = acos(x);
    assert_eq!(acos_of_x.call(1.), 0.);