Here's a tip for people new to Maple or to 2-D input: always use a space for implied multiplication. 2-D math input in Maple allows for implicit multiplication, which is writing a multiplication operation without an explicit multiplication operator. An example is x y.
The space is not always required in cases where there is no ambiguity. However, it is highly recommended that you include it. An example that catches many new users (and some experienced ones as well) is s(t+u). This does not mean s times t+u, but the function s applied to t+u
An exception to this rule is when the multiplier is a constant. By default, 2(x+y) is interpreted as 2 times x+y rather than the operator 2 applied to x+y. (Note that this expression entered in 1-D math returns the value 2.) See the 2DMathDetails help page for more information about changing this default behavior and further details about implicit multiplication.