What you have to do here is show that the derivative of:Originally Posted bywcwalberg

satisfies:

,

and that .

The second of these is trivial; just plug in place of in the

definition of to find .

For the first part you need to differentiate:

to find . To do this you need to use

the product rule on the first term on the RHS (the second term is a

constant and so has derivative ):

.

Here we let , and , then

and the result should follow.

RonL