1 . tan-12x1-x2=sin-12a1+a2+cos-11-b21+b2

• A. $\frac{a-b}{1+ab}$
• B. $\frac{a+b}{1-ab}$
• C. $\frac{2ab}{1+ab}$
• D. $\frac{2ab}{1-ab}$

Answer: Option B

Explanation: