Results 1 to 6 of 6

Math Help - Quadratic inequalities

  1. #1
    Junior Member
    Joined
    Sep 2008
    Posts
    73

    Quadratic inequalities

    Two inequality questions (not related)

    1. if k does not equal 0 solve the quadratic inequation for all real values
    k^2x+kx+2k<0
    2. Consider the quadratic equation ax^2+px+aq+q=0 where, a does not equal 0 & p and q are constants.
    It is known that one of the roots of the quadratic equation is always 1 regardless of the value of a. Prove that p+q=0
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5
    Quote Originally Posted by requal View Post
    Two inequality questions (not related)

    1. if k does not equal 0 solve the quadratic inequation for all real values
    k^2x+kx+2k<0

    Mr F asks: What pronumeral is being solved for .... x or k?

    2. Consider the quadratic equation ax^2+px+aq+q=0 where, a does not equal 0 & p and q are constants.
    It is known that one of the roots of the quadratic equation is always 1 regardless of the value of a. Prove that p+q=0
    2. If x = 1 is always a root then a + p + aq + p = 0 => p + q + a(1 + q) = 0. Since a \neq 0 it follows that if p + q = 0 then q = -1. So it seems to me that the statement is only true if q = -1.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Junior Member
    Joined
    Sep 2008
    Posts
    73
    doesnt say but i think its referring to x though i guess if u solve one of them you will know the other
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5
    Quote Originally Posted by requal View Post
    doesnt say but i think its referring to x though i guess if u solve one of them you will know the other
    I too thought it might be x except that it's linear, not quadratic in x ....
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Junior Member
    Joined
    Sep 2008
    Posts
    73
    yep my bad; it is actually a typo; its supposed to be k(x^2)+kx+2k<0
    i think is the second time this has happened. No wonder it takes so long for people to respond to my posts
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Member
    Joined
    Dec 2008
    From
    Indiana
    Posts
    127
    Quote Originally Posted by requal View Post
    yep my bad; it is actually a typo; its supposed to be k(x^2)+kx+2k<0
    i think is the second time this has happened. No wonder it takes so long for people to respond to my posts
    Hi requal,

    In that case, you could just divide by k both side since k is not zero.
    Then you are just working with x^2+x+2 < 0

    You may want to check the signs though, it seems like there is no real solution...

    Edit:
    My bad, if k > 0, the answer is "no real solution" like shown above.
    if k < 0, then the "<" switches ">" when divided by k, which would mean the answer is all real numbers.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Quadratic Inequalities
    Posted in the Algebra Forum
    Replies: 1
    Last Post: April 2nd 2011, 12:05 AM
  2. Quadratic Inequalities
    Posted in the Pre-Calculus Forum
    Replies: 6
    Last Post: February 1st 2010, 04:44 AM
  3. Quadratic Inequalities
    Posted in the Pre-Calculus Forum
    Replies: 1
    Last Post: January 31st 2010, 05:05 AM
  4. Quadratic inequalities
    Posted in the Algebra Forum
    Replies: 3
    Last Post: February 27th 2009, 07:30 AM
  5. Replies: 1
    Last Post: June 12th 2008, 10:30 PM

Search Tags


/mathhelpforum @mathhelpforum