Question

(sec A +tan A - 1)(secA-tanA+1)=


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Answer 1

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$= ( \frac{1}{ \cos \: q } + \tan \: q - 1)( \frac{1}{cos \: q} - tan \: q \: + 1)$

$= ( \frac{1 - cas \: q}{cas \: q} )( \frac{1 + cas \: q}{cas \: q} )$

$= \frac{( {1)}^{2} - co {s}^{2} q}{ co {s}^{2}q }$

$= \frac{sin \: q}{co {s}^{2} q}$