Question

what is the value of D (Discriminant) when roots
are equal​

Answer 1

Answer:

• The value of Discriminant when the roots are equal is 0.

More to know:

The roots are equal when the whole quadratic equation is a whole square.

For ex- x²+4x+4 .

• When we factorise it , it will be (x+2)(x+2) and when we equate it with 0 the two roots will be -2,-2 which us same.
• When we plot its graph it will cut x - axis at only one point.

For a standard quadratic equation in ax²+bx+c form the Discriminant is equal to b²-4ac .

b²-4ac is called discriminant because it describes the nature of the roots.

We find the roots using the standard formula which is -b±√b²-4ac / 2a .

Here we can see that b²-4ac is inside the square root . Hence it determines the nature of roots .

• When D > 0 , roots are real.
• When D = 0 , roots are equal.
• When D < 0 , roots are complex conjugates.