Doug C. answered 02/22/26
Math Tutor with Reputation to make difficult concepts understandable
For a left-right opening hyperbola the general form is:
(x-h)2/a2 - (y-k)2/b2 = 1
where the center of the hyperbola is at (h, k), "a" is the distance from center to a vertex, and "b" is the distance from the center to the conjugate axis. The slopes of the asymptotes are b/a and -b/a. Both asymptotes pass through the center of the hyperbola.
That means in order to write the equations of the asymptotes you can use point-slope. The slope is b/a passing through (h,k): y - k = (b/a)(x - h) or y = k + (b/a)(x - h). Similarly for the asymptote with slope -b/a.
The vertices, center, and foci all lie on the transverse axis. So every one of those points has the same y-coordinate.
Looking at the given problem one of the asymptotes has the equation:
y = 1/3 + (1/4)(x + 1)
So, b = 1, a = 4, h = -1, k = 1/3
Center: (-1. 1/3).
Vertices will be a horizontal distance of 4 from the center:
V1 = (-1 + 4 , 1/3) = (3, 1/3)
V2 = (-1 - 4, 1/3) = (-5, 1/3)
"c" is the distance from the center to a focus, and c2 = a2 + b2.
c = √(16 + 1) = √17
F1 = (-1 + √17, 1/3)
F2 = (-1 - √17, 1/3)
The equation of the hyperbola:
(x + 1)2/16 - (y - 1/3)2/1 = 1
desmos.com/calculator/oho6xzujjw
To sketch the graph, pinpoint the center, graph the vertices, lightly sketch the conjugate axes (y = 1/3 ± 1), which allows you to locate the corners of the auxiliary rectangle, graph the asymptotes. Finally sketch the hyperbola by starting at a vertex and use the asymptotes to constrain the location of the two branches.