Question

4sin^2 x=-4sin (-x)-1

Answer 1

$4sin^2 x=-4sin (-x)-1$
$4sin^2 x=4sin x-1$
$4sin^2 x-4sin x+1=0$
Замена: $sinx=a,$  $|a| leq 1$
$4a^2-4a+1=0$
$(2a-1)^2=0$
$2a-1=0$
$a=0.5$
$sinx=0.5$
$x=(-1)^k frac{ pi }{6} + pi k,$ $k$ ∈ $Z$