Angle Between Two Tangents

Angle Between Two Tangents

For the ellipse:

$$\frac{x^2}{a^2}+\frac{y^2}{b^2}=1$$

the angle between two tangents from an external point can be determined from the slopes $$m_1$$ and $$m_2$$ using:

$$\tan\theta=\left|\frac{m_1-m_2}{1+m_1m_2}\right|$$

Usage

- Used when the slopes of the two tangents are known or can be determined.