Quadratic Equation

also7

For the quadratic equation, does the discriminant include the square root symbol?

For example, in the problem x^2+7x+6, is the discriminant sqrt25 (5) or 25?

**Posted:** Wed Nov 04, 2009 2:54 pm

Tomekk

Hello,

$b^{2}-4ac$ would be discriminant.

**Posted:** Wed Nov 04, 2009 2:59 pm

also7

Thank you.

**Posted:** Wed Nov 04, 2009 5:13 pm

fishythefish

The square root is not needed because you can determine whether the root exists based only on the sign of the discriminant.

Let $D$ be the discriminant:

If $\text{sgn}{D}>0$ then there are two real roots.
If $\text{sgn}{D}=0$ then there is one real (double) root
If $\\text{sgn}{D}<0$ then there are no real roots

**Posted:** Thu Nov 05, 2009 3:39 pm

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