Ctgx=1/tgx
tgx+1/tgx-2=0
tg²x-2tgx+1=0
tgx=t
t²-2t+1=0
D=2²-4*1=4-4=0
t1=2+0/2=1
t2=2-0/2=1
tgx=1
x=π/4 +πn n∈Z
(1,5*2,4)/0,9=4
.........................
-ab(a²b-ab²-a³b³)=-a³b²+a²b³+a^4b^4
sin^6X+cos^6X+3sin^2Xcos^2X=(sin^2x+cos^2x)(sin^4x+cos^4x-sin^2xcos^2x)+3sin^2xcos^2x=sin^4x+cos^4x+2sin^2xcos^2x=(sin^2x+cos^2x)^2=1^2=1
10x²+5x=0
5x(2x+1)=0
5x=0 или 2x+1=0
x=0 x=-0,5