Question

The angle between the pair of lines $y^2{\sin }^2\theta -xy{\sin }^2\theta +x^2({\cos }^2\theta -1)=0$ is

• A. $\pi /3$
• B. $\pi /4$
• C. $2\pi /3$
• D. $\pi /2$

Answer 1

The correct option is D $\pi /2$

As $a+b={\sin }^2\theta +{\cos }^2\theta -1=0$.
The lines are $\perp$.

Hence the angle between the pair of lines is ${90}^o$