Question

Упростите:

$frac{sin t-1}{cos t} * frac{sin t+1}{cos t}$

Answer 1

ОДЗ: cost≠0

$frac{sint-1}{cost} * frac{sint+1}{cost}= frac{sin^{2}t-1 }{ cos^{2} t} = frac{- cos^{2} t}{ cos^{2} t} =-1$