HP 39gs_40gs_Mastering The Graphing Calculator_English_E_F2224-90010

Special characters
As in the
HOME view, special characters such as inequalities are
available from the
CHARS view, although the appearance of the
CHARS view is somewhat different as can be seen right. There are no
page up/down buttons, which makes it more difficult to move through.
The initial two rows are invalid characters that can’t be used – exactly
why they were included is not clear.
Pressing
will echo the single character under the curser, closing the
CHARS view and returning
immediately to the CAS editing view. Pressing
stores the character to a buffer and allows you to
continue selecting more. You can then either press
ON to exit or use for the final character. If the
character you echo is inappropriate for the situation in the CAS view then it may be rejected.
Using the
CHARS view is not the most convenient method and some commonly used characters are provided
via special keyboard shortcuts.
These are:
SHIFT 0 – inserts ∞
The (-) button also has a special function in the CAS. If you
SHIFT 1 – inserts i (
SHIFT 3 – inserts
π
SHIFT 5 – inserts <
SHIFT 6 – inserts >
−1
)
have entered a variable or constant, pressing
(-) will insert a
negative character before it even if the cursor is currently to
the right of the variable or constant. Pressing
(-) again will
change this to a + (positive) sign.
SHIFT 8 – inserts ≤
SHIFT 9 – inserts ≥
For example, pressing
SHIFT 3 then (-) (-) will result in +
∞
.
This can be very useful when working with limits or integrals.
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