You can use PMT to determine payments
to annuities. For example, if you want to save $60,000
in 20 years by saving a constant amount each month, you
can use PMT to determine how much you must save. If you
assume you'll be able to earn 5.5 percent interest on
your savings, you can use PMT to determine how much to
save each month.
Type the following in line 1,2 and line
3:
| Line 1 |
r=5.5%
;pyr=12 ;n=20*pyr |
| Line 2 |
p12=pmt(r/pyr,
n, 0, 60000,0) |
| Line 3 |
t12=p12*n
;p12 |
| Line 4 |
-137.73 |
Now press [exe] and your monthly payment
is shown on line four.
If you pay $137.73 into a 5.5 percent
savings account every month for 20 years, you will have
$60,000.
Notice the ;p12 at the end of line 3.
The last expression or variable will be shown on line
4.
Now lets see how much you would need to
pay each month when you pay 13 times a year instead of
12.
Change line 1,2 and 3 as shown:
| Line 1 |
r=5.5%
;pyr=13 ;n=20*pyr |
| Line 2 |
p13=pmt(r/pyr,
n, 0, 60000,0) |
| Line 3 |
t13=p13*n
;p13 |
| Line 4 |
-127.10 |
Now press [exe] and your monthly payment
is shown on line four.
Now put your stylus on the equal sign
in line 3 and highlight the rest of line 3. Select [menu][edit][cut]
which will only leave t13 on line 3 and press [exe].
| Line 1 |
r=5.5%
;pyr=13 ;n=20*pyr |
| Line 2 |
p13=pmt(r/pyr,
n, 0, 60000,0) |
| Line 3 |
t13 |
| Line 4 |
-33046.21 |
The total amount paid is now shown on
line 4.
Change t13 into t12 and press [exe]. This
is the total amount paid when you would pay 12 times a
year instead of 13 times, every month instead of every
four weeks.
Now you can type t12-t13 at line 3 and
press [exe].
Of course if this is something you would
need on a regular basis you can copy it to one of the
eight users program. I normally need to delete a user
program first before I can add an other one. Don't forget
to copy and paste to memopad before deleting a program.
Type the following in a user program:
| R=4.7K ;C=10n ;w=2*pi*1K |
| s=j*w ;H=1/(1+s*R*C) |
| Fc |
Fc=1/(2*pi*R*C) |
| an |
angle=arg(H) |
| pd |
PhaseDelay=-angle/w |
| |
|
| |
|
| |
|
Press [ok] and line 1 and 2 should appear.
Note: Version 3.1 is needed for the suffixes
K and n in line one.
After pressing the user defined key [an]
the lines 3 and 4 should appear.
| Line 1 |
R=4.7K
;C=10n ;w=2*pi*1K |
| Line 2 |
s=j*w
;H=1/(1+s*R*C) |
| Line 3 |
angle=arg(H) |
| Line 4 |
-16.45 |
Line 4 shows the angle for this lowpass
filter at 1 khz.
Now press Fc to calculate the cutoff.
3386.28 will be shown at line four.
Change the 1K at line one to 3386.28 and
press [an]. It will show an angle of -45 degrees at the
cutoff frequency.
| Line 1 |
R=4.7K
;C=10n ;w=2*pi*3386.28 |
| Line 2 |
s=j*w
;H=1/(1+s*R*C) |
| Line 3 |
angle=arg(H) |
| Line 4 |
-45.00 |
Pressing pd will show:
| Line 1 |
R=4.7K
;C=10n ;w=2*pi*3386.28 |
| Line 2 |
s=j*w
;H=1/(1+s*R*C) |
| Line 3 |
PhaseDelay=-angle/w |
| Line 4 |
2.115m |
Feel free to try this on any other calculator
for the palm pilot :-)
: empty
