Angle Between Two Lines in General Form

Angle Between Two Lines in General Form

## Formula

For:

$$A_1x+B_1y+C_1=0$$

and:

$$A_2x+B_2y+C_2=0$$

the angle between them satisfies:

$$\tan\theta=\left|\frac{A_1B_2-A_2B_1}{A_1A_2+B_1B_2}\right|$$

## Usage

- Used to find the angle between two lines directly from their general equations.