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Question: The equation \(\frac{x^{2}}{1 - r}\)– \(\frac{y^{2}}{1 + r}\)= 1, r \> 1 represents...

The equation x21r\frac{x^{2}}{1 - r}y21+r\frac{y^{2}}{1 + r}= 1, r > 1 represents

A

An ellipse

B

A hyperbola

C

A circle

D

None of these

Answer

None of these

Explanation

Solution

x21r\frac{x^{2}}{1 - r}y21+r\frac{y^{2}}{1 + r}= 1; (r > 1)

Let r = 2 Ž x2(1)\frac{x^{2}}{( - 1)}y23\frac{y^{2}}{3}= 1

Ž 3x2 + y2 = –3

Ž 3x2 + y2 + 3 = 0

It is not a circle, ellipse and hyperbola.

\ none of these

Note : If (r < –1) Ž then equation is an ellipse

and if (–1 < r < 1)

Ž then equation represents a hyperbola.