Question

упростите
$\frac{1 - cos ^{2}7y }{cos ^{2}7y }$
$(1 - cosx)(1 + cosx) \times ctg ^{2} x$
$\sqrt{1 - cos ^{2} \beta }$
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Answer 1

$\frac{sin^{2}7y }{cos^{2} 7y} =tg^{2}7y$

$(1-cos^{2} x)*\frac{cos^{2}x }{sin^{2}x } =sin^{2}x*\frac{cos^{2}x }{sin^{2}x } =cos^{2}x$

║sinx║