if `(secA+tanA)(secB+tanB)(secC+tanC)=(secA-tanA)(secB-tanB) (secC-tanC)` Prove that each of the side is equal to `+-1.`

Explanation

To prove that if

\[ (\sec A + \tan A)(\sec B + \tan B)(\sec C + \tan C) = (\sec A - \tan A)(\sec B - \tan B)(\sec C - \tan C) \]

then each of the sides is equal to \(\pm 1\), we can follow these steps:

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