HP 39gs Master Manual page 69

However, for the scale of -6 to 6 the pixels are no longer 'nice' values of 0.1. If you try to trace the circle
you'll see that the pixels fall on 0, 0.0923077, 0.1846154..... In particular, near x=3 the pixel values are
2.953846 and 3.046154. This means that the calculator can't draw anything past 2.953846 because the
next value doesn't exist, being outside the circle. This is what causes the gap in the circle. There's nothing to
join to past that last point.
If this missing piece is a problem to you then the solution is to use scales which allow the end points of your
circle to fall on a pixel point. If your circle has an integer radius then this is easily done by starting with the
default axes and then
ZOOM
circle is not centered on the origin then just check/tick the box in the Set Zoom Factors box to Recenter. That
will allow you to turn off
be and then .
Trig functions
If you intend to
function and you are using radian measure
then you should choose a scale which will
cause pixel values (screen dots) to fall at
convenient points. A good scale to use is
provided on the
VIEWS
This scale sets each dot to be
π
factors of will fall on dots and thus helping if you want to trace values
on the graph. You can see in the example right that the value of
that the angle measure is set to Radians in the
in or out to show the circle. This will tend to give 'nice' pixel points. If your
, move the cursor closer to the point where you'd like the centre of screen to
the graph of a trig
menu (see right).
π
, ensuring that multiples and most
24
MODES
π
is easily traceable. You should ensure
2
view if you intend to use this scale.
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