If `tanA=(1-cosB)/(sinB)` , then `tan2A=tanBdot`

Explanation

To prove that if \( \tan A = \frac{1 - \cos B}{\sin B} \), then \( \tan 2A = \tan B \), we can follow these steps:

### Step 1: Start with the given equation
We have:
\[ \tan A = \frac{1 - \cos B}{\sin B} \]

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