#3a. The tree has to form a straight chain in order to produce Omega(n) upon one bad operation. A straight chain tree form by multiple insertions of nodes with keys arrange in sequential order. ex: 1,2,...,n-1, n. lookup(1) will take Omega(n) time. Moreover, lookup(1) reduces the height to about half its original height. Interestingly, continuation of Lookup(2)...Lookup(n) will put the tree back to its original state.
#3b. I inserted 2^n nodes where n ranges from 0 to 20. Each successful iteration of the 2^n of ascending keys from 0 to 2^n will produce a straight chain tree then follow by 2^n lookups on random key in the tree. A straight line produce; y = 0.7535x + 3.2812. The constant C is about 0.7535.jhaja