Let A'A be the transverse axis, and along the conjugate axis measure off CB and CB', each equal to b. Through B and B' draw parallels to the transverse axis and through A and A' parallels to the conjugate axis, and let these meet respectively in K1, K2, K3, and K4, as in the figure.
Clearly the equations of K1CK3 and K2CK4 are
and these are therefore the equations of the asymptotes.
