First slide

Pair of straight lines

Question

The equation $\sin^{2} {θx}^{2} + 2 kxy + \cos^{2} {θy}^{2} = 0$ represents coincident lines then k is

Easy

A

$- sinθ cosθ$
B

$\pm sinθ cosθ$
C

$sinθ cosθ$
D

$\sin 2 θ$

Solution

The condition that the equation ${ax}^{2} + 2 hxy + {by}^{2} = 0$ to represents coincident lines is $h^{2} = ab$
Hence, $k^{2} = \sin^{2} {θcos}^{2} θ$
It implies that $k = \pm sinθcosθ$

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App