106
Asish Mahapatra
·2010-02-04 21:36:05
Q3. An equation touching the x-axis means that there is a repeated root there. So, atleast 2 real roots are there of f(x) where it tuches x-axis
And as two roots are real and coefficients are rational so all three roots are real
106
Asish Mahapatra
·2010-02-04 21:39:07
Q1. 0 ... as x=√3 is a repeated root (repeated twice)
and for rational coefficients we have irrational roots occuring in pairs... So x= -√3 is also a repeated root (twice)
So sum of roots = 0
106
Asish Mahapatra
·2010-02-04 21:41:08
Q2. If f(x) touches x-axis at only one point then there is a repeated root.
Further if that root is irrational, then its conjugate (if u know wat i mean) will also be a root... But it is given that it touches exactly at one point.. which is contradictory if there is rational point (where it touches)
So that point has to be real where f(x) touches the x-axis