Решение
[1 - 1/ctg²(π/2 + x)] * sin²x = (1 - 1 / tg²x) * sin²x =
= (1 - cos²x/sin²x) * sin²x = (sin²x - cos²x) = - cos2x
4sin(2π+a)=sina
cos(3π/2+a)=sina
4sina-4sina+7=7
S(ABP)=S(ABD)-S(APD)
S(CDP)=S(ACD)-S(APD)
S(ABD)=1/2AD*h и S(ACD)=1/2AD*h ⇒S(ABD)= S(ACD)⇒S(ABP)=S(CDP)
(a³*a⁴)/a¹¹=a⁷/a¹¹=1/a⁴=1/(-0.5)⁴=1/0.0625=16
<span>2sin (4pi/3-x) -sin (4pi/3+x)= 0
-2sin(</span>π/3-x)+sin(π/3+x)=0
-2sinπ/3cosx+2cosπ/3sinx+sinπ/3cosx+cosπ/3sinx=
=-sinπ/3cosx+3cosπ/3sinx=-√3/2*cosx+3*1/2*sinx=-√3/2cosx+3/2*sinx
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-√3/2cosx+3/2*sinx=0/cosx
3/2*tgx-√3/2=0
3/2*tgx=√3/2
tgx=-√3/3
x=-π/6+πk,k∈z