
Algebra PreAlgebra and Basic Algebra Math Forum 
 LinkBack  Thread Tools  Display Modes 
June 20th, 2012, 07:47 AM  #1 
Senior Member Joined: Sep 2011 Posts: 395 Thanks: 0  Sum & Product of the Roots of a Quadratic Equation
Having a bit of trouble with this one. Can anyone help me out? Many thanks. Q. For what value of m are the roots of the equation equal but opposite in sign. Attempt: Sum of roots: => => => Product of roots: => => => => => => => => => => => ... Ans.: (From text book): m = 1 
June 20th, 2012, 07:59 AM  #2 
Member Joined: Jun 2012 From: UK Posts: 39 Thanks: 0  Re: Sum & Product of the Roots of a Quadratic Equation
You were virtually there, and then wandered off into deep doodoo. Just considering the sum of the roots gets you to (m+1)/3=0 and hence m=.... The only other thing you need to consider is that the product of the roots is nonzero (otherwise both roots are zero), and that's true, so you're done. 
June 20th, 2012, 08:12 AM  #3  
Math Team Joined: Dec 2006 From: Lexington, MA Posts: 3,267 Thanks: 407  Re: Sum & Product of the Roots of a Quadratic Equation Hello, bilano99! You had the answer . . . You just zoomed past it. Quote:  
June 20th, 2012, 08:34 AM  #4 
Senior Member Joined: Sep 2011 Posts: 395 Thanks: 0  Re: Sum & Product of the Roots of a Quadratic Equation
D'oh!!! Thanks, guys.

June 20th, 2012, 09:32 PM  #5 
Global Moderator Joined: Dec 2006 Posts: 18,551 Thanks: 1477 
If the roots are p and p, where p > 0, the equation is effectively 3(x + p)(x  p) = 0, i.e. 3x²  3p² = 0, so m = 1.


Tags 
equation, product, quadratic, roots, sum 
Search tags for this page 
sum and product of quadritic equation,is s(sum of product) and p(product of product) what is quadratic equation
Click on a term to search for related topics.

Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
quadratic equation roots  bongantedd  Algebra  3  February 22nd, 2014 08:10 AM 
Sum & Product of the Roots of a Quadratic Equation  bilano99  Algebra  5  April 21st, 2013 07:08 PM 
Quadratic Equation Ratio of roots  sachinrajsharma  Algebra  1  February 20th, 2013 09:11 AM 
Sum & Product of the Roots of a Quadratic Equation  bilano99  Algebra  4  June 18th, 2012 10:26 AM 
Create a quadratic equation with roots + and  i?3/4  Baseball72Twins  Algebra  2  January 6th, 2012 04:14 PM 