If the line y=mx+cy = mx + cy=mx+c is a tangent to the hyperbola x2a2−y2b2=1\frac{x^2}{a^2} - \frac{y^2}{b^2} = 1a2x2−b2y2=1, which relation must hold?
c2=a2m2+b2c^2 = a^2m^2 + b^2c2=a2m2+b2
c2=a2m2−b2c^2 = a^2m^2 - b^2c2=a2m2−b2
c2=b2m2−a2c^2 = b^2m^2 - a^2c2=b2m2−a2
c2=a2−b2m2c^2 = a^2 - b^2m^2c2=a2−b2m2