HP 42S manual Getting used to some keys of the keyboard

this case the content just entered appears only once.

So if you do 2 1/x or another example 9 √x what you will have will be

i)Only the content of the line 4 (line t) will be lost.

ii)The content of line 3 (z) goes to line 4 (t). iii)The content of line y goes to line 3 (z). iv)The content of line x goes to line y.

v)Your result will be in the first line x.

This second way to enter data looks more intuitive to me and I think it should be aways like this. But it is not!:( So to do 2+3 we have to do

2 ENTER 3 + (and not 2 ENTER 3 ENTER +).

(Actually one can also use EXIT to enter a number without duplication)

If you just press ENTER you duplicate what is in line x.

When making a calculation one should never forget about the limitation of the 4 lines of the stack.

The lines of the stack cannot contain only numbers but also matrices, complex numbers, etc.

The basic operations with the stack are: x><y and R↓. The first changes line x with line y. The second makes the stack rolls down (line y goes to line x, line x goes to line t, line t goes to line z and line z goes to line y)

In the CLEAR Menu there are some interesting functions: CLST which clears all the stack (something missing in HP-33S). CLX clears the line x in the same way of pressing ←.

The ← is more used to correct a number when typing it.

Another useful function is ▀ LASTx which gives the last calculated result.

2.8 Getting used to some keys of the keyboard

Let's discuss some basic keys of the calculator. We will start from superior left side.

Σ+ and ▀ Σ- : These are statistical functions. We will discuss this later.

1/x and ▀	y x	: 1/x just calculate the inverse of a number which is in line x.
		▀	yx is the potential function. To calculate 53 = 5.5.5 we do
		5 ENTER 3 ▀ yx .
√x and ▀	x2	: These functions just calculate the square root and the square of a number in line x.
		When studying complex numbers we will see that unlike HP-33S in HP-42S the
		number in square root can be negative.
LOG and ▀		10x	: These functions calculate the base 10 logarithms and it's inverse.
			These things were important before the era of calculators so there is no reason

to have them in one.