Sin5xcos4x - cos5xsin4x = 0
sin(5x - 4x) = 0
sinx = 0
x = πk, k∈z
tg540=0 т.к sin540=0
cos(П-3П/4) + 0; -cos(П-П/4)+0= cosП/4 + 0= (корень 2)/2
(9/(m²-3m+9)+2m/(3+m)-(m³-15m²)/(m³+27)=
9/(m²-3m+9)+2m/(3+m)-(m³-15m²)/[(m+3)(m²-3m+9)]=
=(9m+27+2m³-6m²+18m-m³+15m²)/(m³+27)=
=(m³+9m²+27m+27)/(m³+27)=(m+3)³/[(m+3)(m²-3m+9)=(m+3)²/(m²-3m+9)