HP 40gs User Manual page 293

Part 6
Step-by-Step Examples
Now press
the graphs.
To find the values of
return to CAS, type each function in turn and press
. (You may need to press
simplification).
For example, pressing
X 0
gives the result at the right:
Likewise, pressing
π
X
gives this
answer at the right:
The other results are:
2π 1
⎛ ⎞
----- - -- -
X =
⎝ ⎠
3 4
3
X π ( )
-- -
=
2
Y 0 ( )
= 0
π
– 3
⎛ ⎞
-- - --------- -
Y =
⎝ ⎠
3 4
⋅
2π – 3
⎛ ⎞
----- - -----------------
Y =
⎝ ⎠
3 4
Y π ( )
= 0
The slope of the tangents is
We can find the values of
using the lim command.
to see
x t ( ) y t ( )
and for
3
3
y' t ( )
--------- -
m =
x' t ( )
y' t ( )
--------- -
t
for
x' t ( )
-- - 2 π ⋅ π
, , ---------- π ,
t = 0
3 3
twice for further
.
π -- - 2 π ⋅
, , ---------- π ,
= 0
by
3 3
16-19