** Using WeBWorK **

Yes, it "works" in this case, but it is bad practice, and won't always work. When used as arguments to a function, arrays are "flattened" I.e., f((1,2),(3,4)) is the same as f(1,2,3,4), so your array of one value is the same as passing one value directly, but the semantics are wrong, and it is a bad habit to make arrays when you mean scalars.