Show that: `cos(2tan^(-1)(1/7))=sin(4tan^(-1)(1/3))`

Explanation

To show that \( \cos(2\tan^{-1}(1/7)) = \sin(4\tan^{-1}(1/3)) \), we will evaluate both sides step by step.

### Step 1: Evaluate the Left-Hand Side (LHS)

We start with the LHS:

\[
\text{LHS} = \cos(2\tan^{-1}(1/7))
...