1. Not finding help here? Sign up for a free 30min 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!

Question on the slope of the tangent

  1. Mar 5, 2007 #1
    Find the points on the graph of y= (1/3)x^3-5x- (4/x) at which the slope of the tangent is horizontal.

    what i know:
    - we have to use m=[f(a+h)-f(a)]/h
    - if we change the equation we can get 3x^4 - 15x^2 -12
    - the slope of the tangent is zero.

    THANX
     
  2. jcsd
  3. Mar 6, 2007 #2

    jtbell

    User Avatar

    Staff: Mentor

    hint: how does the derivative of a function relate to the slope of the tangent of its graph?
     
  4. Mar 6, 2007 #3

    Gib Z

    User Avatar
    Homework Helper

    Find the derivative, and set it equal to the slope of a horizontal line. What is that?
     
  5. Mar 6, 2007 #4

    HallsofIvy

    User Avatar
    Staff Emeritus
    Science Advisor

    What everyone is saying is "DO IT"! By the way are you really required to use the "quotient difference" formula? It's not too difficult but tedious and most problems like this allow the use of derivative formulas.
     
  6. Mar 6, 2007 #5

    jtbell

    User Avatar

    Staff: Mentor

    Do you mean, "what is the slope of a horizontal line?"

    Draw a graph that shows a horizontal line. Pick two points [itex](x_1,y_1)[/itex] and [itex](x_2,y_2)[/itex] on the line. Do you know how to calculate the slope of a line from two points?
     
  7. Mar 7, 2007 #6

    Gib Z

    User Avatar
    Homework Helper

    yes thats what i meant, but i knew the answer..set the derivative to zero is what i meant
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Question on the slope of the tangent
  1. Slope of tangent (Replies: 12)

Loading...