1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Still that problem.

  1. Jan 14, 2005 #1
    Well, Sorry but I couldn't find help @ Homework section, I try out here:
    Ok, they tell me to find a and b so that the function:
    f(x)= *Root(2-x^2) if -root(2)<=x<=1
    *x^2 + ax + b if x>1
    has derivative at 1
    I got that the condition for this graph to be continous at 1 is a+b=0
    And I moved to check out the derivative stuff:
    When x->1+, the derivative is 0
    But when 1->1-, igot stuck:
    lim (x->1+) of [f(x)-f(1)]/(x-1) = lim (x->1+) of [x^2+ax+b-1]/(x-1)] (from the function at my first post, I got that when x>1, f(x)=x^2+ax+b) How can I figure out the relation between a and b so that I can put it and the one above to an equation?
    Help me please, thanks!
  2. jcsd
  3. Jan 14, 2005 #2


    User Avatar
    Science Advisor

    What are you expecting? People to answer your question within a few minutes?
  4. Jan 14, 2005 #3
    Sorry, mein Fehler
  5. Jan 14, 2005 #4
    Very sorry. I though there are many guys here in the forums. sorry alot!
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook