Question

The value of $\tan ({180}^o+\theta )$. $\tan ({90}^o+\theta )$ is

• A. $1$
• B. $-1$
• C. $0$
• D. None of these

Answer 1

The correct option is B $-1$

$\tan ({180}^{\circ }+\theta )\times \tan ({90}^{\circ }+\theta )$

$=-\tan \theta \times \cot \theta$

$=-\tan \theta \times \frac{1}{\tan \theta }$

$-1$