Online Course Discussion Forum

Geometry 3.9

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Geometry 3.9
by Tina Jin - Tuesday, August 30, 2022, 4:33 PM


I remember that Mr. John replied to my question of this same question before, but I got the answer and it is 2sqrt(2)pi+4sqrt(2).  Is that right? Thanks!

Picture of John Lensmire
Re: Geometry 3.9
by John Lensmire - Wednesday, August 31, 2022, 5:41 PM

Hi Tina. This doesn't seem quite right, but seems close!

The path should have 3 parts:

  1. From the origin to a point on the circle
  2. Traveling around a portion of the circle
  3. From the circle back to the origin

It's hard to say without seeming more details, but it looks like you have the 1st and 3rd parts correct, that it is 2sqrt(2) from the origin to the tangent point on the circle for a total distance of 4sqrt(2).

Where does the second portion come from? As a hint, it should be traveling around 3/4 of the circle, right?