For the hyperbola ` (x^(2))/( cos ^(2) alpha ) -(y^(2))/(sin^(2) alpha ) =1` ,which of the following remains constant when `alpha ` varies?

For the hyperbola (x^(2))/(cos^(2)alpha)-(y^(2))/(sin^(2)alpha)=1; (0

For the hyperbola (x^(2))/(cos^(2)alpha)-(y^(2))/(sin^(2)alpha)=1 which of the following remains constant when varies? (1) eccentricity (2) directrix (3) abscissae of vertices (4) abscissae of foci

For the hyperbola (x^2)/(cos^2alpha)-(y^2)/(sin^2alpha)=1 , which of the following remains constant when alpha varies? (1) eccentricity (2) directrix (3) abscissae of vertices (4) abscissae of foci

For the hyperbola x^2/(cos^2alpha)-y^2/(sin^2alpha)=1 , which of the following remains constant when alpha varies ?

For the hyperbola x^2/ cos^2 alpha - y^2 /sin^2 alpha = 1;(0 lt alphalt pi/4) . Which of the following remains constant when alpha varies?

For the hyperbola x^2/ cos^2 alpha - y^2 /sin^2 alpha = 1;(0 lt alphalt pi/4) . Which of the following remains constant when alpha varies?

For the hyperbola x^2/ cos^2 alpha - y^2 /sin^2 alpha = 1;(0 lt alphalt pi/4) . Which of the following remains constant when alpha varies?

For the hyperbola (x^(2))/(cos^(2)alpha)-(y^(2))/(sin^(2)alpha)=1;(0