Q.

The foci of a hyperbola are (±2,0) and its eccentricity is 32. A tangent perpendicular to the line 2x+3y=6 is drawn at a point in the first quadrant on the hyperbola. If the intercepts made by the tangent on the x- and y-axes are a and b respectively, then |6a|+|5b| is equal to _________ .        [2023]


Ans.

(12)

e=32, ae=2

a=43e2=1+b2a2

54=9b216b2=54×169=209

Equation of tangent:  y=mx+a2m2-b2

y=32x+169·94-209

y=32x+43

y-intercept=43,  x-intercept=-89

|6a|+|5b|=|6×-89|+|5×43|=163+203=363=12