Sin²2x+sin²4x=(1-sin²x)+(1-sin²3x)
sin²2x+sin²4x=cos²x+cos²3x
(1-cos4x)/2+(1-cos8x)/2=(1+cos2x)/2+(1+cos6x)/2
1-cos4x+1-cos8x=1+cos2x+1+cos6x
cos4x+cos8x+cos2x+cos6x=0
2cos6xcos2x+2cos4xcos2x=0
2cos2x(cos6x+cos4x)=0
2cos2x*2cosx*cos5x=0
cos2x=0⇒2x=π/2+πn⇒x=π/4+πn/2,n∈z
cosx=0⇒x=π/2+πn,n∈z
cos5x=0⇒5x=π/2+πn⇒x=π/10+πn/5
3х^2+8х+2=0; делим на 3;
х^2+2*4/3х+16/9-16/9+2/3=0;
(х+4/3)^2=16/9-6/9=10/9;
х+4/3=+-(10^1/2)/3; х=-4/3+-(10^1/2)/3;
х1=(-4-10^1/2)/3; х2=(-4+10^1/2)/3.
<span>36,40+19,50=55,90 (за 1м.куб со сливом)
304-293=11 м.куб
11*55,90=614,9
Вроде так)</span>