How to signal to the reader the difference between a function and a multiplication? The following is alpha of t times x:
$$\alpha(t)x$$
The following is alpha times t times x:
$$\alpha(t)x$$
My instructor had one interpretation, I used the other. ;)
Is there an easy or standard way to signify that we're talking about a function rather than a variable multiplication here?
 A: Just a suggestion: we can simply write $\alpha t x$ to mean the product of the three variables. Usually it is clear from the context what the meaning is: if $\alpha$ is a function, then $\alpha (t)$ would be the function evaluated at $t$.
A: For "alpha times t times x" I would suggest writing
$$
\alpha\cdot t\cdot x
$$
and adding brackets if appropriate, like $(\alpha\cdot t)\cdot x$. You could also leave the centered dots.
The bracket in $\alpha(t) x$ does not make much sense.
A: I have noticed that misinterpretations of notation are becoming more common. For instance, many students have difficulty when differentiating something such as y = sin(tan(x)), mistakenly interpreting it as a product as opposed to a composition. Jasper makes a good point when he emphasizes that the context is usually a good guide as to how to interpret. In my example, the function sine has to act on something, which would be tan(x). As a rule, if you are unsure how to interpret, ask for clarification. If the situation does not allow that, or the instructor declines to comment, closely examine the context.
