22b. List Exercises 3

Note: This page uses MathJax to show fancy formulas.

1. random-gen: number(N) -> list of numbers. Generate N random numbers, each one in the interval $-150 \le x \le 150$ . Example (random so numbers will be different each time):

    (random-gen 5) => (list -75 100 -30 50 21)
   

2. parabola-it: list of numbers -> list of posn. Use the numbers as the x-coordinates of function

   $$f(x) = 0.01 * x^2 - 50$$

    (parabola-it (list 5 10)) => (list (make-posn 5 -49.75) (make-posn 10 -49))
   

3. people-graph: list of posn -> image. Place the posns in people coordinates on a 300x200 rectangle with origin at the center.

   

A quick check to make sure everything is in order is to run all of the functions together:

(people-graph (parabola-it (random-gen 50)))