Spreadsheets and Graphing
Finding minimum surface area of a cylindrical can with fixed volume
Draw circle from sin and cos values in spreadsheet
From circle to spiral: modify plot of sin and cos values
More geometric patterns from sin and cos values
http://dl.dropboxusercontent.com/u/4210789/dg/dots.html
Plotting cosine graph and transform
http://dl.dropboxusercontent.com/u/4210789/dg/cos_shift.html
See how the cos wave seems to move to the left. If you focus on each dot, they are simply moving up and down. Each dot is repeating movement of another on its right, but remaining on the same horizontal position. That's how the over all pattern seems to move in the opposite direction.