Expert: Paul Klarreich - 8/23/2011

Question
Hi, I have a question about finding the derivative. My problem is y = 1 - ln(x)/2 + x^2
I understand that this turns into (2 + x^2)(-1/x) - (1 - ln(x)) (derivative of 2 + x^2) all divided by 2 + x^2 squared? I'm not really sure about how to find the derivative of 2 + x^2 though, or for anything else for that matter! (This is all new to me and my maths is not extremely good.) So any help would be very much appreciated!
Thanks for your time,
Erin

Answer
Questioner:Erin
Country:New South Wales, Australia
Category:Calculus
Private:No
Subject:finding the derivative

Question:

Hi, I have a question about finding the derivative. My problem is y = 1 - ln(x)/2 + x^2
I understand that this turns into (2 + x^2)(-1/x) - (1 - ln(x)) (derivative of 2 + x^2) all divided by 2 + x^2 squared? I'm not really sure about how to find the derivative of 2 + x^2 though, or for anything else for that matter! (This is all new to me and my maths is not extremely good.) So any help would be very much appreciated!
Thanks for your time,
Erin
...............................................
"the derivative of 2 + x^2"

is the easiest part of the whole exercise.  My suggestions:

1. State what rule you are using, before you start.
2. Use the vocabulary correctly.  Don't say "turns into" (a phrase used by magicians) when you mean "its derivative is".
3. Separate parts of a complex exercise to focus your attention.

"2 + x^2"  is a polynomial.  By now, you should have learned how to find its derivative.