Picture Frame Using GeoGebra

For the whole file, see here
 

A sewing machine got me doodling...

Imagine what you could do if you only starting playing around with Geogebra!!
 

Do tires travel in circles?

or
The whole GeoGebra file can be found here.

A Challenge Problem

What is mathematical about a boat?

The animation to the right is a cropped version of a Geogebra file. The actual file is here.

Everything that was used to create the Geogebra file involves knowledge that should be gained by a high school trig student.

(I am assuming that in the age of technology the concept of "phase shift" has become an integral part of a trig course.)

I did use the built-in tangent line function, rather than go through the task of using calculus operations to find the same result.

For those who want to see how the tangent line is actually identified, make sure to pay attention in your Calculus class.

As long as the notion of tangent lines is on the table, I suggest you take a look at this (the original is here)