Condition for Positive Roots

Condition for Positive Roots

## Formula

For a quadratic with real coefficients to have both roots positive:

$$D\ge0$$

$$\alpha+\beta>0$$

$$\alpha\beta>0$$

For:

$$ax^2+bx+c=0$$

this becomes:

$$b^2-4ac\ge0$$

$$-\frac ba>0$$

$$\frac ca>0$$

## Usage

- Used in parameter-based questions requiring both roots to be positive.