Chapter 4 Discussion VI

The alternating series is

[1, -1/2, +1/3, -1/4, +1/5, -1/6, ...]

1. Define altTerm n to be the nth term in the sequence.

2. Define altSeq m to be the list of the first m terms in the sequence.

3. Write a function to find the sum of the first k terms of the alternating series.

4. Write waltSum, which takes in a list of numbers, multiplies each term by the corresponding term in the alternating series, and then adds up the sums.

   Example:

    waltSum [5,10,15] == 1*5 + (-1/2)*10 + (1/3)*15
   

5. The goalt x function adds up the terms in the alternating series until it comes on a term that is less than x in absolute value.

   Example:

    goalt 0.21 == 0.5833...
   

Remember: fromIntegral when you need to divide something by an Int.