Question

решите,пожалуйста. тригонометрия. cos x/sin2x =cos x

Answer 1

$frac{cosx}{sin2x} = cosx$
$frac{cosx}{2sinx*cosx} = cosx$
$frac{1}{2sinx} = cosx$
$frac{1}{2sinx} = cosx \ 1 = 2sinx*cosx \ 1 = sin2x$
2x = π/2 + 2πk
x = π/4 + πk