The first one is correct. The second is not, the first term of the second derivative should actually be .
This is because , which you would then use the power rule for.
c) Your first two terms are correct. For the third term, rewrite it as:
Now you just have a constant times x.
For the 4th term, let's write:
take the natural log of both sides:
Implicitly differentiate:
d) For the first term you need to apply the product rule, and for the second term use:
e) Apply the quotient rule.
f) Correct.
g) You neglected to apply the chain rule to the argument of the trigonometric term in the numerator. Otherwise, it is correct.
j) In the denominator of the result, you want the first binomial factor to be squared. I would write the result as: