S=ah
S=3×7=21
роаоамлмпочоапчаоп
Cosx=(ab)/(|a| *|b|)
cosx=(2*(-4)+(-2)*1+1*1) /(coren(2^2+(-2)^2+1^2)(c0ren(-4)^2+1^2+1^2))=
=-9/(coren9 *coren18)=-9/)3*3coren2)=-1/coren2
x=pi-pi/4=3pi/4
10-2*(-3) =16 10-2*(-1)=12 10-2*0=10 10-2*2=6 10-2*3=4 10-2*4=2 10-2*6=-2
10+2*(-3)=4 10+2*(-1)=9 10+2*0=10 10+2*2=14 10+2*3=16 10+2*4=18 10+2*6=22
1) 1/2 - ( 1/2 )^2 • 2/23 = 1/2 • ( 1 - ( 1/2)•2/23 ) = 1/2 • ( 1 - ( 1/23 )) = 1/2 • 22/23 = 11/23
2) 25 • 0,03 • 4 = ( 25 • 4 ) • 0,03 = 100 • 0,03 = 3
3) 11/23 - 3 = 11/23 - 2 23/23 = - 2 12/23