### A RipStik sine wave in trigonometry class done right

For test six in MS 101 Algebra and Trigonometry I opted to lead off with a wave equation question built on an actual RipStik wave done just before class on the day of the test. I tried a eastbound downhill run from the Learning Resource Center, but the speed was too fast. On a single sheet of poster paper I had at best half a wavelength and an amplitude of maybe three centimeters. I tried the uphill from the north faculty building, but that was too steep. My runs were crooked, wobbly, irregular, and generated chaotic waves. I then opted for a westbound run towards the LRC in front of the south faculty building, placing two 82 cm long poster pad papers on the ground. I did a steady swizzle run up the slope trying to ensure that my centerline was straight. I focused on a point at the far end of the sheets, and worked to ensure my track was straight. Whether I would achieve a sine, negative sine, cosine, or negative cosine was not within my control.

The RipStik moved from right to left above, with the left exit edge providing a nice sine wave.

Moved onto the board the numbers were at seen above. The centerline was one of the straightest I have achieved in many a term. A warped meter stick up in A101 provided just the right amount of curve to get a good center line down the middle of the slightly wavering center line. The run was moderately slow, as can be seen by the 1.47 seconds to cover 164 centimeters. The amplitude was about as good as I get on a cruise run. All-in-all I was rather pleased with the result, especially the unexpected sine wave start on the left side. I had thought I might have to trim the paper to start the wave on a clean sine wave as the test presumes a sine wave. Of course one could phase shift anything to be a positive sine wave, but that is confusing for my students and beyond their current ability.