Question

If the angle between the lines represented by the equation $\tan^{2}A = 0$be $2A$, then $k =$

• A. 0
• B. 1
• C. 2
• D. $\tan A$

Answer 1

Answer: (A)

0

Answer 2

Here $\tan 2A = \frac{2\sqrt{\frac{k^{2}}{4} + \tan^{2}A}}{1 - \tan^{2}A}$

$\Rightarrow \frac{2\tan A}{1 - \tan^{2}A} = \frac{2\sqrt{\frac{k^{2}}{4} + \tan^{2}A}}{1 - \tan^{2}A}$

$\Rightarrow \frac{k^{2}}{4} + \tan^{2}A = \tan^{2}A \Rightarrow k = 0$ .