I'll just help ya for the first problem because the second is very easy.
Put so that and now we can apply the power rule but, always! having in mind the chain rule, thus Finish it!
Power rule: which gives us the correct answer of which simplifies to . Your answer is visually far more complex and another thing, not that you really used any, but it seems like the vast majority of people do not know math notation. I think with some of the answers a KISS approach would really help some people. Sorry for posting in an ancient thread that someone revived.
I realize that, however, my point really is that if the question is something you would normally do in your head the person posing question would probably like the simplest answer/explanation possible and it seems like people often get the complete opposite. I also think some of these people are too damn smart!
Yes, it can be much easier to do these sorts of tasks without writing them out, but the extra exposition can be helpful for someone who is not as experienced. As the individual gains in experience, he or she will gradually need to write out less steps.