Tinh gia tri bieu thuc:
43/9:(-5/18)+48/9(-18/5)
tinh gia tri bieu thuc
A = 2*125*18+36*252+4*223*223*9
Cho phan thuc B=(3\y+3)+(1\y-3)-(18\9-y2)
a)Tim dieu kien cua y de gia tri cua bieu thuc B duoc xac dinh
b)Rut gon bieu thuc B
c)Tinh gia tri cua B de B co gia tri nguyen
tinh gia tri bieu thuc
a,1002 nhan 9 - 18
tinh gia tri bieu thuc: B=1*2*3+2*3*4+3*4*5+...+17*18*19
B = 1.2.3 + 2.3.4 + 3.4.5 + .... + 17.18.19
<=> 4B = 1.2.3.4 + 2.3.4.4 + 3.4.5.4 + .... + 17.18.19.4
<=> 4B = 1.2.3.(4 - 0) + 2.3.4.(5 - 1) + 3.4.5.(6 - 2) + .... + 17.18.19.(20 - 16)
<=> 4B = 1.2.3.4 + 2.3.4.5 - 1.2.3.4 + .... + 17.18.19.20 - 16.17.18.19
<=> 4B = 17.18.19.20 = 116280
<=> B = 116280 : 4 = 29070
B = 1.2.3 + 2.3.4 + 3.4.5 + .... + 17.18.19
<=> 4B = 1.2.3.4 + 2.3.4.4 + 3.4.5.4 + .... + 17.18.19.4
<=> 4B = 1.2.3.(4 - 0) + 2.3.4.(5 - 1) + 3.4.5.(6 - 2) + .... + 17.18.19.(20 - 16)
<=> 4B = 1.2.3.4 + 2.3.4.5 - 1.2.3.4 + .... + 17.18.19.20 - 16.17.18.19
<=> 4B = 17.18.19.20 = 116280
<=> B = 116280 : 4 = 29070
tinh gia tri cua bieu thuc: B=1*2*3+2*3*4+3*4*5+4*5*6+.....+17*18*19
Gia tri bieu thuc [3/7 + 2/7] - 1/5 = ............
A 15/35 B 18/35 C 15/7 D 4/9
GIUP MINH VOI MINH DANG CAN GAP
Tinh gia tri cua bieu thuc (-1+2/5).(-1+/2/9).(-1+2/9).............(-1+2/2013)
tinh gia tri bieu thuc 1+2+3...+16+17+18
tinh gia tri nho nhat cua cac bieu thuc sau: Q=9/2+|2/5-x|
x2-2x+5
=x2-2x+1+4
=(x-1)2+4
Vì:
Min = 4 khi x=1