tgx=y'
y'=(x²-2)'(x²+2)-(x²-2)(x²+2)' / (x²+2)² = 2x(x²+2)-2x(x²-2)/(x²+2)²=
=2x³+4x-2x³+4x/(x²+2)² = 8x/(x²+2)² = 8*2/(2²+2)²=16/36 =4/9
tgx=4/9
x=arctg 4/9
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y=sin4xcos4x=1/2 sin8x
y'=1/2 *cos8x * 8=4cos8x=4cos 8π/3 = 4cos (2π+2π/3)= - 2 четверть ,cos отриц.
=-4cos π/3 = -4*1/2=-2
tgx=-2
x=-arctg2+πn , n∈Z