Prove that:
`tan7A-tan5A-tan2A=tan7Atan5Atan2A`

Explanation

To prove the identity \( \tan 7A - \tan 5A - \tan 2A = \tan 7A \tan 5A \tan 2A \), we will start with the left-hand side (LHS) and manipulate it to show that it equals the right-hand side (RHS).

### Step 1: Rewrite \( \tan 7A \)
We can express \( \tan 7A \) using the angle addition formula:
\[ \tan 7A = \tan(5A + 2A) \]
Using the formula \( \tan(a + b) = \frac{\tan a + \tan b}{1 - \tan a \tan b} \), we have:
...