Question

The angle between the pair of straight lines $y^{2}si{n}^2\theta -xysi{n}^2\theta +x^2(co{s}^2\theta -1)=1,$ is

• A.
• B.
• C.
• D. $\frac{\pi }{2}$

Answer 1

The correct option is D

$\frac{\pi }{2}$

$\alpha =ta{n}^{-1}\left\{\frac{2\sqrt{\frac{si{n}^2\theta }{4}-si{n}^2\theta (co{s}^2\theta -1)}}{si{n}^2\theta +co{s}^2\theta -1}\right\}$

=$ta{n}^{-1}\infty \Rightarrow \alpha =\frac{\pi }{2}$