Don you need help with just those two or all of the ones in the middle, too?
Here are some hints for those two:
In 59, imagine you have a monotone function and they asked you the same thing. What is the result of that sum?
Now, look at the regions over which this is monotone and apply the same thing.
For 65, notice it's easily factorable. Factor it and it becomes quite an easy diff eq.