Higher Derivatives Question

Hi all,

Here goes the question:

Given that , show that .

I am quite comfortable in deriving the normal and higher derivatives(*Just to make sure I am on the right track, is =sin3x-3sin3x+3xcos3x?) and am more concerned about the 'showing' part. Hopefully someone can guide me along.

Another one:

Given that , prove that .

It seems like a typical implicit diff. question other than the higher derivatives part. I haven't really learn how to derive higher derivatives using implicit diff.

Any help is appreciated. Thanks in advance!