1)<span>sin ( a-3п/2 )* cos ( п-a ) - sin ( a-п )*sin ( п+a )=сosa*(-cosa)-(-sina)*(-sina)=
=-cos²a-sin²a=-1
2)</span><span>4cos ( a-п ) + ctg ( -3п/4 )* sin ( 3п/2 )=4*(-cosa)-1*</span>(-1)=-4cosa+1
3)<span>sin ( a-п ) + tg ( a - п ) + cos ( a + 3п/2 ) =-sina+tga+sina=tga
tga=tga
</span>
C=2πr
C=2*3,14*24=150,72 (см)
C=2*3,14*4,7=29,51(дм)
C=2*3,14*18,5=116,18(м)
А) 1/6 + 1/9 = 3/18 + 2/18 = 5/18
б) 2/9 + 5/6 = 4/18 + 15/18 = 19/18
в) 2/9 + 3/8 = 16/72 + 27/72 = 43/72
г) 2/10 + 6/15 = 6/30 + 12/30 = 18/30
д) 3/10 + 2/12 = 18/60 + 10/60 = 28/60
е) 5/12 + 4/15 = 25/60 + 16/60 = 41/60
ж) 3/4 + 5/18 = 27/36 + 15/36 = 42/36
з) 2/26 + 3/39 = 6/78 + 6/78 = 12/78
и) 7/34 + 5/51 = 21/102 + 10/102 = 15/102
к) 4/210 + 5/140 = 8/420 + 15/420 = 23/420
л) 7/450 + 8/180 = 14/900 + 40/900 = 54/900
м) 9/180 + 7/120 = 18/360 + 21/360 = 39/360
1. ........................=2 2/3
1) 2 2/3 :2=8/3 * 1/2=4/3=1 1/3
2) 4/15+2/5=4/15+6/15=10/15=2/3
3) 3 1/3 * 3/5=10/3 * 3/5=2
4) 2/3*2=4/3=1 1/3
5) 1 1/3 + 1 1/3=2 2/3
2. ..............................=8 1/20
1) 2 : 1/4=2*4=8
2) 1 1/2+2 2/3=1 3/6+2 4/6=3 7/6=4 1/6
3) 4 1/6 : 3 3/4=25/6 * 4/15=10/9=1 1/9
4) 1 1/9 - 2/3=1 1/9 - 6/9=10/9-6/9=4/9
5) 4/9 : 8 8/9=4/9 * 9/80=1/20
6) 8+1/20=8 1/20