4sin^2x(sinz+1)-3(sinx+1)=0
sinx=-1 x=-П/2+2Пk
4sin^2x-3=4-4cos^2x-3=1-4cos^2x=0
cosx=+-1/2
x=+-П/3+2Пk
x=(П+-п/3)+2Пk
1.cos^2(\pi+t)+cos^2(\pi-t)=
=cos(\pi+t)*cos(\pi+t)+cos(\pi-t)*cos(\pi-t)=
=(-cos(t))^2+(-cos(t))^2=2cos^2(t)
2. cos(2\pi-t)-sin(3\pi/2+t)=1
cost+cost=1
2cost=1
cost=1/2; t=\pi/3
3. sin(2\pi-t)-cos(3\pi+t)-1=0
-sint-cos(\pi+t)=-1
-sint+cost=-1
sint-cost=1
sint [-1;1]; cos[-1;1] => sint=1: cost=0
t=\pi/2
-0,512
все просто
-0.8*(-0.8)*(-0.8)=-0.512
А) (-корень из 3)/2
б) -1/2=-0.5
4а^2b-a^4+9-4b^2 =-a^4+4A^2b-4b^2+9 умножим на минус 1