Details for Wednesday Afternoon

  A series: 
    -- a number: a Sigma(i=0..N)(f i), 
       now: sum of all squares, sum of2^i/i!, ...

    ;; sum-x-square : natural-number[n] -> number
    ;; result: sum(i=0)(i=n)(f i)
    (define (sum-f N)
      (cond
	((zero? N) (f 0))
	(else (+ (f N) (sum-f (- N 1))))))

    ;; i
    (define (f i) i)

    ;; i^2
    (define (f i) (* i i))

    ;; e^2 @ i : 2^i/i!
    (define (f i) (/ (expt 2 i) (! i)))
    (define (! n) (if (= n 0) 1 (* n (! (- n 1)))))

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  Structs in lists

    -- list of balls: extract list of positions
    -- list of personnel records: extract list of names+salaries

RECAP: nat nums : natnum -> list-of "series of e^i for i = 0, ..., 10"

ASSIGNMENTS: choose teams, let them choose: 

  - Section 13.3: series of rectangles [well-suited for graphical
    illustration of geometric series on TAAS]
or
  - Section 12.2: protect the wall [fun, more realistic]