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!

Homework Help: Two different tangents which are perpendicular?

  1. Nov 2, 2008 #1
    1. The problem statement, all variables and given/known data
    Does the curve y=x^2 have two different tangents which are perpendicular? Does the curve y=x^3?

    3. The attempt at a solution
    I have no idea how to prove that for x^2 or x^3.
    (x^2)' =2x that is tangent at a point x
    then m = -1/2 x for another point....
    How do i prove that there is sucha point? then how about x^3?
     
  2. jcsd
  3. Nov 2, 2008 #2

    HallsofIvy

    User Avatar
    Science Advisor

    Re: Differentiation

    Two lines are perpendicular if and only if the product of their slopes is -1. So the question is, "are the two different values of x, say x1 and x2, such that (2x1)(2x2)= -1?"
    For the cubic, the corresponding equation is (3x12)(3x22)= -1.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook




Loading...