Question 1: Very nice. However, what made you assume that the amount of plants is described by a logistic growth?
Question 2(a) Correct.
Question 2(b) Unfortunately, your derivative of y' with respect to x is not -1+2x^2 but -1+3x^2, and the error propagated. Luckily,
you got the right conclusions, and therefore there was no reason to suspect that there was a mistake.
Question 2(c) As usual, you include very pleasant pictures. Your picture made in the Phaser program looks very beautiful. You forgot to
explain why the spiral is clockwise. To do this you need to choose an arbitrary point (x,y) on the plane and then you draw the arrow at (x,y) using the
formula (x',y')=A.(x,y).
Question 2(d) Correct.