V=(4/3)*PI*R^3=(4/3)*PI*6^3=288*PI
Cos^2(30)-2sin^2(30)=3/4-1/20=1,4;
<span>3 cos²45°-2 cos²60°=3/2-1/2=1;
</span><span>4 sin30°- √3 cos30°=2-1.5=0.5;</span>
1) x -y -(x^2 +y^2)/(x-y) =
= [(x-y)^2 -x^2 -y^2]/(x-y) = (x^2 -2xy +y^2 -x^2 -y^2)/(x-y) = -2xy/(x-y) = 2xy/(y-x)
2) (a^2 +b^2)/(a+b) -a -b =
= [a^2 +b^2 -(a+b)^2]/(a+b) = (a^2 +b^2 -a^2 -2ab -b^2)/(a+b) = -2ab/(a+b)
Все отмеченные треугольники равны по признаку равенства двух сторон и угла между ними
4/10 * 1/3 = 4/30
5/6 * 12/10 = 60/60 = 1
4/30 / 1 = 4/30 = 2/15
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25/10 = 5/2
5/2 * 4/5= 20/10 = 2
16/10 = 8/5
8/5 * 3/4 = 24/20 = 6/5
2 / 6/5 = 2 * 5/6 = 10/6 = 5/3