no, it is asking you to derive the formula given. i'll do the hard part.

Consider the function

since , we have that:

differentiating both sides implicitly with respect to , we get:

.....................................note, we used the chain rule on the LHS

differentiating implicitly again, we obtain:

......note, we used the product rule (and chain rule) on the LHS

solving for , we get:

Now, all you need to do, is prove that and you will have the desired result