Better Students Ask More Questions.
Q. Let a,b,c `in` R. Let there exist two real roots of `ax^2 + bx + c=0` .If `ax^2 + bx...
Q. Let a,b,c `in` R. Let there exist two real roots of `ax^2 + bx + c=0` .If `ax^2 + bx + c >0` for all x `in` [-1,1] then `(1 + c/a + |b/a|)` is
a) always positive
b) always negative
c) sometimes positive sometimes negative
d) always zero
My teacher told that answer is (b) but how??
1 Answer | add yours
High School Teacher
`f(x)=ax^2+bx+c >0 AA x in[-1,1]`
`b> -a-c` (ii)
from (i) and (ii)
`-a-c < b< a+c`
So answer (a) is true.
Posted by aruv on July 13, 2013 at 3:50 AM (Answer #1)
Join to answer this question
Join a community of thousands of dedicated teachers and students.