Flag Algebra> quadratic equation...
question mark

The range of values of a for which roots of the quadratic equation x^2+x-3a+2=0 are of opposite sign is given by

a) a<1

b) a>2

c) 1

d) 0

Shohini Sinha Ray , 16 Years ago
Grade Upto college level
anser 1 Answers
askIITIians Expert

Your given equation is

x2 + x – 3a + 2 = 0

Since the roots are opposite in sign, so α x β is –ve                  (i)

Hence,

α x β = -3a + 2/1                 (ii)

Therefore, product of roots of the eq.

ax2 + bx + c = c/a

From equation (i) and (ii), we have

-3a + 2 < 0

-3a < -2

a > 2/3                           (i)

Also, discriminant D should be greater than 0 for roots to be real

Hence, 1 – 4 (-3a + 2) > 0

1 > 4(-3a + 2)

-12a + 8 < 1

-12a < -7

a > 7/12                          (ii)

Taking the intersection (i) and (ii) we have,

a > 2/3

Hence, the most appropriate option is (b) a > 2 , since a > 2/3

Then, a > 2.

Last Activity: 16 Years ago
star
LIVE ONLINE CLASSES

Prepraring for the competition made easy just by live online class.

tv

Full Live Access

material

Study Material

removal

Live Doubts Solving

assignment

Daily Class Assignments