22b. List Exercises 3
Randomly generate points on a parabola and graph them in people coordinates.
Note: This page uses MathJax to show fancy formulas.
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random-gen
: number(N
) -> list of numbers. GenerateN
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)
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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))
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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)))