71) Solution of inequality 2|x+1| > x+4 contains which interval?
2) If R is a relation from a finite set A having m elements to a finite set B having n elements, then find the number of relations from A to B.(with proof)
1. All the three roots of equation x3 –- 3x +1 = 0
lie on the interval
(A) [–2, 0] (B) [–1, 1]
(C) [–2, 2] (D) [–1, 2]
2. If ax2 + bx + c, a, b, c belog to R has no real zeros
and if a + b + c < 0 then
(A) c > 0 (B) c < 0
(C) c = 0 (D) None of these
3. If x2 + ax + b = 0 and x2 + bx + a = 0 have
common root then numerical value of a + b is
(A) 2 (B) 1
(C) –1 (D) None of these
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3 Answers
211)(-2,2) ??
2)f(x) = ax^2 + bx + c
f has not real root. f(1)<0
f(x)<0 for all x
f(0)<0 , c<0
3)let x1 be the common root
x12+ ax1 + b = x12+bx1+ a
x1 = 1
so 1 satisfies both the equations. so a+b = -1
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49Solutions in here:
http://www.targetiit.com/iit-jee-forum/posts/beginners-series-quadratic-equation-19482.html