Prove that: `t a n 70^0=t a n 20^0+2t a n 50^0dot`

Explanation

To prove that \( \tan 70^\circ = \tan 20^\circ + 2 \tan 50^\circ \), we can follow these steps:

### Step 1: Use the tangent subtraction formula
We start with the formula for the tangent of the difference of two angles:
\[ \tan(a - b) = \frac{\tan a - \tan b}{1 + \tan a \tan b} \]
Let \( a = 70^\circ \) and \( b = 20^\circ \). Then we have:
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