-- PARABOLA -By Simon Carter
Parabola Plotter is a
general-purpose program for plotting
Parabolas. Most Parabolas are plotted in under 10 seconds. It
requires Microworld Disk Basic version 6.30e.
Change equation
With the main menu displayed, press <1>, for "Change equation".
The screen will clear and the following will appear :
Previous equation y = x^2
This line tells you the previous equation plotted.
When you
first start this will always be set to y = x^2, but will change
when you enter another equation.
Please enter the value of A, where y = A( x + b )^2 + c
or <CR> for default of 1 : -.07
<CR>
This value determines the shape of the graph. A negative value
will turn it upside down (-1, -23, -4.5) and a positive value
will make it upright (1, 13, 8.7).
A large value will make
it thin (5, -16, 9.5), while a small value will make it fat
(.3, -.07, .07). Pressing <CR> will set A to its default value
of 1. Pressing <SPACE> will give A its previous value.
Please enter the value of B, where y = -0.07( x + B )^2 + c
or <CR> for default of 0 : -2
<CR>
This value determines the graph's X position. A negative value
(-2, -5, -.5) will move the graph to the right.
A positive
value (4, 8, 3.5) will move the graph to the left. Pressing
<CR> will set B to its default value of 0.
Pressing <SPACE>
will give B its previous value.
Please enter the value of C, where y = -0.07( x - 2 )^2 + C
or <CR> for default of 0 : 9
<CR>
This value determines the graph's Y position. A negative value
(-4, -12, -3.5) will move it down and a positive value (2, 7,
5.4) will move it up. Pressing <CR> will set C to its default
value of 0.
Pressing <SPACE> will give C its previous value.
If B has not been specified, the brackets will not appear.
Are you plotting the graph of y = -0.07( x - 2 )^2 + 9
<Y>es or <N>o
(Default Yes)
If this line displays the correct equation, press <CR> or <Y>.
If it isn't right, press <N> and type it in again.
The axis and scales will be drawn, and a message
telling you which equation is being plotted.
will be printed
Change axis
With the main menu in front of you, type <2>, for "Change axis".
The screen will clear and the following lines will appear one at a
time on the 17th line :
To move (0,0) horizontally, type -250 to 250 or 0 centre :____
This value effects where the Y axis appears on the screen. A
negative number will move it left from the centre, a positive
number will move it right from the centre. Pressing <CR> will
set it to its default value of 0.
Pressing <SPACE> will
set it to its previous value. Only integers are allowed.
To move (0,0) vertically, type -120 to 120 or 0 centre :____
This value effects where the X axis appears on the screen. A
negative number will move it down from the centre and a
positive number will move it up from the centre. Pressing
<CR> will set it to its default value of 0. Pressing <SPACE>
will set it to its previous value.
Only integers are
allowed.
X - axis scale factor (Default 1) :____
This value effects the number of scale marks on the X axis. A
small number (0.5, 0.1) will increase the number of marks, a
large number (1.5, 3) will decrease the number of marks.
Pressing <CR> will set it to its default value of 1. Pressing
<SPACE> will set
it to its previous
value.
Negative
numbers are not allowed.
Y - axis scale factor (Default 1) :____
This value effects the number of scale marks on the Y axis. A
small number (0.5, 0.1) will increase the number of marks, a
large number (1.5, 3) will decrease the number of marks.
Pressing <CR> will set it to its default value of 1. Pressing
<SPACE> will set
it to its previous
value.
Negative
numbers are not allowed.
Confirm <Y>es or <N>o
(Default Yes)
This line just asks for confirmation of the settings. If they
are wrong, press <N> and go through them again, otherwise press
<Y> or <CR>.
A message will appear telling you which equation is being plotted
and then the Parabola will be drawn.
Change equation and axis
Press <3> while in the main menu.
previous 2 sections put together.
This is
the
same as
the
Re-plot graph
Press <4>
equation.
while in
the main
menu.
This
will re-plot
the last
Quit
Press <Q> while in the main menu.
This message will appear :
Are you sure (Y or N)
If you do wish to exit to the system, press
<N> to get back to the main menu.
<Y>, otherwise press
Screen Dumps
After the graph has been plotted, a message will appear :
Press <S> for screen dump, <CR> for menu.
If you press <CR> you will return to the main menu. If you press
<S> the current graph will be dumped to a parallel printer.
ou pr