Category Archives: Uncategorized

floor(x) and ceiling(x)

Simon Woodhead writes:

Floor and ceiling functions are not available in the current version of Autograph, but will be in a future version. The y = int(x) function is actually a truncation function so int(-3.2) = -3 and int(3.2) = 3. This is not the most useful function, but can be used to define ceiling and floor functions.

Open a 2D graph page and click on Function Definitions. Define:
  f(x) = ((int(x) + |int(x)|) + (int(x − 1) − |int(x − 1)|))/2
  g (x) = f(x) + 1
Then f(x) is the floor function and g(x) is the ceiling function.

floot

Modelling a bottle in 3D

bottle

First import the image, and enter lots of points along the top edge.

Select a group of points that you think could be modelled by a polynomial and use the “best Fit” option.  The default ‘sig’ fig’ is 4, but a polynomial equation needs more accuracy to plot accurately.  Use “PAGE – SETTINGS” to set the sig fig to 8. With the current best fit selected, use the PAGE menu  and the option “Copy Status Bar”, and in a 3D page use “Enter equation” and paste this in, with “Plot as 2D” ticked, and Startup Options set to the domain.

bottle2In the 3D page, select each sector, use “Find Area” with “Simpson’s Rule” selected, then “Volume” about y = 0.

bottle3

 

Wacom Intuos pen and touch small PEN TABLET, and Windows 8

wacom If you are using the latest WACOM pen tablet, with wireless kit
(and you should be!!) there are problems with Windows 8. The symptoms are that the initial action of the pen is a mess,

To solve this it is necessary to UNTICK the option “Use Windows Ink”. This is found in the CONTROL PANEL => Wacom Tablet Properties, and proceed to the MAPPING tab, and the link to untick is in the bottom left

wacom

Details of the Wacom tablet are linked from TSM Resources for the busy teacher  (scroll down a bit)

Autograph: onscreen keyboard

The onscreen keyboard allows Autograph users to input one-line mathematical expressions using a wide variety of symbols that are coorrectly interpreted, eg
   sin²2θ, 2x−3y≤6, −b±√(b²−4ac), y=|x|
It is also invaluable when using a whiteboard or a walk-about tablet.
This short video explains

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