A fun math estimation question inspired by Kate Nowak

Saw this tweet from Dan Anderson today:

@k8nowak Love the gist of the presentation. How did you expect students would solve this problem? + pic.twitter.com/gItA1rxo2Q

— Dan Anderson (@dandersod) November 23, 2015

The rotated graph caught my eye and I started playing around a little. Can’t say that I’d spent much time thinking about rotations of the graph of before, so I was surprised to find that any small (non-zero) rotation about (0,0) – no matter now tiny the angle – produces a point on the graph having a vertical tangent line. It also causes the rotated graph to intersect the y-axis.

Here are two fun estimation question. Don’t calculate or use the fun computer program below, just try to estimate:

(1) For a rotation of 1 degree counterclockwise, what is the x-coordinate of the point with the vertical tangent line?

(2) For a rotation of 1 degree counterclockwise, what is the y-coordinate of the point where the rotated curve crosses the y-axis?

After you think about those questions – so no cheaty cheat cheating! – play around with this graphing tool that David Griswold made:

@dandersod @mikeandallie @TracyZager @k8nowak @rdkpickle Desmos with rotation slider. https://t.co/3wtHET7fFN

I did it implicitly.

— David Griswold (@DavidGriswoldHH) November 23, 2015

Definitely had some fun playing around with these rotations today!

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