Choose the One Alternative That Best Completes the Statement or Answers

Multiple Choice

Choose the one alternative that best completes the statement or answers the question.
Complete the identity.
- $\cos \left( \tan ^ { - 1 } \mathrm { v } \right) = ?$

A) $v \sqrt { v ^ { 2 } + 1 }$
B) $\frac { \sqrt { v ^ { 2 } - 1 } } { v ^ { 2 } - 1 }$
C) $\frac { \sqrt { v ^ { 2 } + 1 } } { v ^ { 2 } + 1 }$
D) $\frac { v \sqrt { v ^ { 2 } + 1 } } { v ^ { 2 } + 1 }$