Exercise 3A-2 e: differentiating published solution (presented using 2 methods) gives a different function: x(8-2x^2)^1/2
It should give x(8-2x^2)^-1/2

my solution is -1/2 (8-2x^2)^1/2 +C
(sorry for my lame equations)

Question

Exercise 3A-2 e: differentiating published solution (presented using 2 methods) gives a different function:         x(8-2x^2)^1/2 
It should give x(8-2x^2)^-1/2

my solution is -1/2 (8-2x^2)^1/2 +C
(sorry for my lame equations)

anonymous · Answer

Yes, that's an error in the solutions provided in the materials. They substituted u^(1/2) when they should have substituted u(-1/2).

anonymous · Answer

Thanks again Creeksider! I'm wondering if there's an errata to the exercise solutions that i've missed?

anonymous · Answer

There are quite a few errors in the exercises and solutions, though most are in exercises that aren't assigned in this course. Take a stab at 2E-4, for example, in the second set of exercises. I sent in my correction for 2C-10 and received a nice thank you note in reply but that was months ago and still no correction has been posted, so I haven't bothered sending corrections for other exercises. Somewhere on the site it says Professor Jerison prepared these exercises but I find it hard to believe anyone who performs so brilliantly in lecture could do such a poor job on these exercises, so my guess is that it was an assistant who could have used closer supervision. Unfortunately I'm taking my time getting around to exercises beyond the third set, so I may not be able to help if you run into further issues.