F=ma
m=F/a
m=84H /12m/c^2
m=7
120*0,4=48см-высота
48:0,75=64см-ширина
120*48*64=368640см³-объем
<span> 3 3/7* 2 1/3</span>=24/7*7/3=8
<span>7 1/3*2 2/11=22/3*24/11=16</span>
(3,15+2 1/12-1/3):(7,3-0,4*8,5) = (3,15+25/12-4/12):(7,3-3,4) = (3,15+21/12):3,9 = (945/300+525/300):3,9 = 1470/300:3,9 = 4,9:3,9 = 1,25461(025461)
Sina=(1-(cosa)^2)^1/2=(1-25/169)^1/2=12/13
sin2a=2*sina*cosa=2*12/13*5/13=120/169
cos(п/3-a)=cos(п/3)*cosa+sin(п/3)*sina=√3/2 * 5/13 + 1/2 * 12/13=5√3/26+12/26=(5√3+12)/26