The Chart & List Window offers a convenient function graphing
facility. Select Function Graph from the window's Chart menu to show the function graph, as shown
below.
DreamCalc Function Graphing
Function Input
Available Functions
- Operators: ^, +, -, *, /, %, !
- Variables: x, t
Alternatively, rather than hitting return to input your function, you may create a dual plot by designating
your input as either plot "A" or "B". Click the drop-down arrow next to the "Enter" button to do this.
See below.
Enter as Plot A or B
The input expression is not case sensitive, and the prefix "y=" is not necessary. The maximum graphing
numerical range is: -1E100 < x or y < 1E100. Complex numbers are not supported in graphing.
You can also use the Axes menu to show logarithmic axes or to map your plot on to a polar grid.
See also: Graphing Examples.
Parametric Variable
You may use the parametric variable "t" in your input expression in place of "x". In this case, DreamCalc
will generate a Polar Plots.
Function Settings
Graphing Angle Mode
The Function Graph has it's own angle mode, as indicated by the radio buttons in the top right of the window.
This angle mode is independent of the calculator's main angle mode. It defines the operation of the
trigonometric functions when the function plot is created. After changing the angle mode, you must re-input your
function by clicking Enter.
Axis Range
Prior to plotting your function, you should specify the desired range of x using the MIN/MAX range edit
boxes. You may use simple expressions in the range boxes, such as: "0.86 * PI".
Alternatively, you may specify the range as part of the function input string itself—using square brackets
and a semi-colon " ; " as the separator.
For example:
sin(x) [0; PI/2]
DreamCalc will strip off the range values and fill out the range boxes for you when the function is entered.
You must, however, specify the interval separately in the Interval or No. Points edit box (see
right).
If you use a period "." as your decimal point you may, if you wish, use a comma as the separator instead of
semi-colon.
No. Points or Interval
DreamCalc needs to know how many data points to generate. You can specify this using:
Specify No. Points
Allows you to specify the number of points, where the corresponding interval will be calculated automatically.
Generally this option is more convenient, as you do not have to re-define the interval for every function plot.
However, it doesn't offer precise control of the values generated as x-inputs to your plot.
Specify Interval
Allows you to specify an interval, giving you precise control over the x values used as input to your
expression. For example, if your range is [0; 10] and you specify an interval value of 1, points will be
generated at integers x = 0, 1, 2, 3... up to and including 10, or eleven points in total. If your input range
and interval define a number of points greater than the maximum number of permissible points, the interval will
be adjusted so as to limit the number of points.
Function Results
Output to X-Y List
When the Output to X-Y List option is checked, chart data is copied to the X-Y list at the time the
plot is generated. You may then edit or export the chart data from the Data List page tab of the
window.
The effect of the Output to X-Y List option is to overwrite the X-Y list each time you generate a
function plot. If you accidently overwrite your list, simply go to the list page tab and click undo to recover
the your original data.
Error Conditions
If no plot could be generated, an applicable error will be shown in the graphing display area.
A plot will be generated, however, if two or more y-value results were successfully calculated over the input
range—even if many other points could not be determined. Often this is to be expected from the nature of the
input; for example, no x-y point will be plotted for the input expression "1 / x" at x=0. In such cases,
DreamCalc will display a small warning message in the graphing area to indicate that not all points were
generated, but otherwise the plot will be shown as normal.
Lengthy Calculations
Generally plots will be generated instantly. However, lengthy functions and/or a high number of data points
may cause DreamCalc to timeout, generating only a partial plot over the desired input range. By default,
DreamCalc will timeout on graphing operations after approximately 5 seconds. You can increase this in Options Window by setting the Timeout option to a value greater than this.
See also: Chart & List Window, Graphing Examples, Polar Plots, Calculus & Intersection Points
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