A <function_call> has a lower precedence than an <operand>, but it has a higher precedence than all the math, comparison, and logical operations. This means you have to be careful about correctly parenthesizing function arguments.
FOR EXAMPLE,
``` sin x + 1
```
is evaluated as:
``` (sin x) + 1
```
In general, you have to put arguments that are expressions inside parentheses,
``` sin (x + 1) atan2 (y - 1) (z - 1)
```
This rule has one exception, the unary minus. It is recognized as one type of <operand> you don’t have to parenthesize.
FOR EXAMPLE,
``` sin -x
```
is interpreted as:
``` sin (-x)
```