Asymptotes of / - / = 1 are y = x and y = -x, or combined: / - / = 0. The asymptotes pass through the center and have slopes +/- b/a. The angle between asymptotes is 2*arctan.
Key property: The equation of the hyperbola, the combined equation of its asymptotes, and the conjugate hyperbola differ only in the constant term. Hyperbola: S = 1, Asymptotes: S = 0, Conjugate: S = -1, where S = / - /.
The conjugate hyperbola -/ + / = 1 shares the same asymptotes and center but has its transverse axis perpendicular to the original. If the original has eccentricity e, the conjugate has eccentricity e' where 1/ + 1/e'^2 = 1.
The rectangular hyperbola xy = (rotation of - = 2 by 45 degrees) has asymptotes as the coordinate axes (x = 0 and y = 0). This form is particularly convenient for problems involving perpendicular asymptotes.
Properties involving asymptotes: (1) Any line parallel to an asymptote meets the hyperbola at exactly one finite point. (2) The perpendicular distance from a focus to an asymptote equals b. (3) The product of perpendicular distances from any point on the hyperbola to the two asymptotes is b^ = /.
JEE application: Finding the equation of a hyperbola given its asymptotes -- the hyperbola equation is the asymptote equation +/- constant.