A formula for the sine function is this:

Write the function sine that takes one input, x (as shown in the formula), in terms of accumulate. It should approximate the sine of the angle (in radians) to 200 terms.

(define (accumulate op id term a next b)
  (cond [(> a b) id]
        [else (op (term a) (accumulate op id term (next a) next b))]))

HINT: This is very similar to problem 1.31 where writing a pi-term function (see Approach #2) was extremely helpful.