Showing posts with label Discriminant of Quadratic Equation. Show all posts
Showing posts with label Discriminant of Quadratic Equation. Show all posts

Wednesday, March 18, 2009

Discriminant Roots of Quadratic Equation

Topic : Quadratic Equation

Question : Explain the Discriminant of a Quadratic Equation

Solution :
Let us consider general quadratic equation ax² ± bx ± c = 0
Discriminant d is given by
d = b² -4ac
a) If d is greater than or equal to 0 , then we have two unequal and real roots.
x1 = (-b + √d)/2a
and x2 = (-b - √d)/2a
b) If d = 0 then we have two real and equal roots.
x1 = x2 = -b/2a
c) if d less than 0 we will be having two unequal and imaginary roots.
x1 = (-b + (√d) i)/2a
and x2 = (-b - (√d) i)/2a