\(A=1+\frac{1}{2}+\frac{1}{2^2}+...+\frac{1}{2^{2014}}\)
\(2A=2+1+\frac{1}{2}+...+\frac{1}{2^{2013}}\)
\(2A-A=\left(2+1+\frac{1}{2}+...+\frac{1}{2^{2013}}\right)-\left(1+\frac{1}{2}+\frac{1}{2^2}+...+\frac{1}{2^{2014}}\right)\)
\(A=2-\frac{1}{2^{2014}}\)
Cho A= 1-2+2^2-2^3+....-2^2013+2^2014
Tinh gia tri cua bieu thuc B= 3A-2^2015
tinh gia tri bieu thuc B =1^2/2^2-1.3^2/4^2-1....2013^2/2014^2-1
Tinh gia tri cua bieu thuc (-1+2/5).(-1+/2/9).(-1+2/9).............(-1+2/2013)
tinh gia tri bieu thuc
A=1+1/2(1+2)+1/3(1+2+3)+....+1/2015(1+2+3+...+2015)
2, 2/5 : 2/3 -1/6
1/2+3×1/6
3,cho bieu thuc A= x ×50 -19,2
a,tinh gia tri cua A voi x= 0,5
b,tinh x khi A= 80,8
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
tim cac dang cua x sao cho
bieu thuc A = 2x-1 co gia tri duong x
bieu thuc B = 8-2x co gia tri am
bieu thuc C=2(x+3) khong am
bieu thuc D=7(2-x)khong duong
cho biểu thức A= a^3 +2a^2-1/a^3 +2a^2+2a+1
a, rut gon bieu thuc
b, CMR neu A la so nguyen thi gia tri cua bieu thuc tim duoc cua cau a la 1 phan so toi gian
