Gujarati
Hindi
10-2. Parabola, Ellipse, Hyperbola
normal

For hyperbola $\frac{{{x^2}}}{{{{\cos }^2}\alpha }} - \frac{{{y^2}}}{{{{\sin }^2}\alpha }} = 1$ which of the following remain constant if $\alpha$ varies

A

Eccentricity

B

Directrix

C

Abscissae of vertices

D

Abscissae of foci

Solution

$\mathrm{a}^{2}=\cos ^{2} \alpha, \mathrm{b}^{2}=\sin ^{2} \alpha$

$e=\sqrt{1+\frac{b^{2}}{a^{2}}}=\frac{1}{\cos \alpha}$

Abscissa of foci $\equiv(a e, 0)=(1,0)$ which is independent of $\alpha .$

Standard 11
Mathematics

Similar Questions

Start a Free Trial Now

Confusing about what to choose? Our team will schedule a demo shortly.