Inverse Trigonometric Functions Question 201

Question: $ {{\tan }^{-1}}\frac{a-b}{1+ab}+{{\tan }^{-1}}\frac{b-c}{1+bc}= $

Options:

A) $ {{\tan }^{-1}}a-{{\tan }^{-1}}b $

B) $ {{\tan }^{-1}}a-{{\tan }^{-1}}c $

C) $ {{\tan }^{-1}}b-{{\tan }^{-1}}c $

D) $ {{\tan }^{-1}}c-{{\tan }^{-1}}a $

Show Answer

Answer:

Correct Answer: B

Solution:

$ {{\tan }^{-1}}( \frac{a-b}{1+ab} )+{{\tan }^{-1}}( \frac{b-c}{1+bc} ) $

$ ={{\tan }^{-1}}(a)-{{\tan }^{-1}}(b)+{{\tan }^{-1}}(b)-{{\tan }^{-1}}(c) $

$ ={{\tan }^{-1}}(a)-{{\tan }^{-1}}(c) $ .