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!

Ok I'm a little confused with this: 16x-y^4=0

  1. Oct 7, 2006 #1
    Ok I'm a little confused with this:


    When you solve for (y) you get: y= plus/minus 4th root(16x) right?
    There for it isn't a function.

    What about y=sq.rt.(1-x)? Does it have the plus/minus automatically? Do you only put the plus/minus sign if you solve for y?

    I just don't get when you have to put the plus/minus in front of the sq.rt. Do you always have to put one there? or only if you solve for y, etc.?
  2. jcsd
  3. Oct 7, 2006 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    Dearly Missed

    Well, the even root of a number is DEFINED to be the positive number.
    That is, by definition, [itex]\sqrt{1-x}[/itex] is a positive number.

    When you solve for y, however, you must remember that not only do you have the positive, even root as a solution, but also the negative of that number.
  4. Oct 7, 2006 #3
    Oh ok. So if they give you an equation that has no plus/minus infront of it, then the equation is POSITIVE. However, if you solve for y and get a sq.rt. then you must put the plus/minus sign right? Thanks.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook