1) Those are polar coordinates
2) The expression inside cosine is the angle of the vector to be drawn
3) r is the length of the vector to be drawn.
For example:
- if you take angle =0 and r results to be =2, it means that you have to put a point over the x-axis at a distance of two units from the origin.
4) You have to look for notable values, like points on the axis and notable angles (0, 45°, 90°, 180 °,...)
5) Use derivation to find maximum and minimum values.
6) The graph of this function looks like the infinite symbol: ∞
7) Some notable points are: (0,0) ; (0,2) ; (0, - 2)
See attached the complete graph as a reference.
