2.1 - fib
2.2 - isSorted
2.3 - curry
2.4 - uncurry
2.5 - compose
3.2 - tail
3.3 - setHead
3.4 - drop
3.5 - dropWhile
3.6 - init
3.9 - length
3.11 - sumLeft, productLeft, lengthLeft
3.12 - reverseFold
3.14 - foldAppend
3.15 - foldCat
3.16 - plusOne
3.17 - dToString
3.18 - fpMap
3.19 - fpFilter
3.20 - fpFlatMap
3.21 - fpFlatMapFilter
3.22 - zipAdd
3.23 - zipWith
3.24 - hasSubsequence
3.25 - fpTreeSize
3.26 - fpTreeMax
3.27 - fpTreeDepth
3.28 - fpTreeMap