There are two ways to do arithmetic on the HP-28S. You can do
arithmetic using the stack, as you did in the previous chapter, or you
can enter an
representing the calculation. In the previous
chapter you calculated:
23) x sin 30°
Here's how to make the same calculation using an expression.
Clear the stack and select the TRIG menu .
• , CLEAR
Start the expression.
The cursor changes, indicating
Algebraic Entry mode.
You'll see the ef-
fects of this entry mode as you key in the expression.
Key in the first part of the expression.
2: Doing Arithmetic