A=1/2*5+1/5*8+1/8*11+...+1/2012*1015
=1/3*(1/2-1/5+1/5-1/8+1/8-1/11+...+1/2012-1/2015)
=1/3*(1/2-1/1/2015)
=1/3*2013/4030
=671/4030
vậy A=671/4030
tinh gia tri bieu thuc:
-1-2+3+4-5-6+7+8-9-10+11+12-...-2013-2014+2015+2016
tinh gia tri cua bieu thuc \
A= (100+98+96+....................+2)-97-95-......-1
B=1+2-3-4+5+6-7-8+9+10-11-12+............-299-300+301+302
Tinh gia tri bieu thuc: C = 1 - 3 + 5 - 7 + ........................+ 2013 - 2015 + 2017
tinh gia tri bieu thuc
A=1+1/2(1+2)+1/3(1+2+3)+....+1/2015(1+2+3+...+2015)
tinh gia tri bieu thuc sau : A=1+2+3+...+2015
tinh nhanh gia tri cac bieu thuc sau
a , 1/ 2+ 1 /3 + 1 / 4 + 1/ 6
b, 53 / 4 . 11/ 16 - 23/4 . 11/16
c, 3/ 8 . ( 2 /9 + 4 /15 )
tinh gia tri cua bieu thuc
b = 1+2-3-4+5+6-7-8 ....-303 -304 +305 +305
b = ......
tim gia tri cua bieu thuc
A=1-2-3-4+5-6-7-8+9-10-11-12+...........+97+98-99-100
Tinh gia tri bieu thuc
G= 8 .52 - {120 - [868 -12 .( 3087 :72 + 20150)]}