Giup minh voi:(1-2015).(2-2014).(3-2013)...(2015-1)
Những câu hỏi liên quan
tinh nhanh bieu thuc sau
a) x^6-20x^5-20x^4-20x^4-20x^3-20x^2-20x+1992 voi x= 21
b)x^7-26x^6+27x^5-47x^4-77x^3+50x^2+x+1989 tai x = 25
c)4029-2015x+2015x^2-....+2015x^2014-x^2015 tai x= 2014
d)A= (x-1/x-2015+x-2/x-2014+x-3/x-2013+....+x-2014/x-2+x-2015/x-1):(1/2 +1/3+1/4+....+1/2016) tai x=2016 dau / o day la phan do nha!!
xin nho cac ban giai giup cho minh! cam on nhieu!!!!!!!! minh dang can ket qua gap
(1/2012+1/2013-1/2014)/(5/2012+5/2013-5/2014)-(2/2103+2/2014-2/2015)/(3/2013+3/2014-3/2015)
\(\frac{\frac{1}{2012}+\frac{1}{2013}-\frac{1}{2014}}{\frac{5}{2012}+\frac{5}{2013}-\frac{5}{2014}}-\frac{\frac{2}{2013}+\frac{2}{2014}-\frac{2}{2015}}{\frac{3}{2013}+\frac{3}{2014}-\frac{3}{2015}}\)
=\(\frac{\frac{1}{2012}+\frac{1}{2013}-\frac{1}{2014}}{5\left(\frac{1}{2012}+\frac{1}{2013}-\frac{1}{2014}\right)}-\frac{2\left(\frac{1}{2013}+\frac{1}{2014}-\frac{1}{2015}\right)}{3\left(\frac{1}{2013}+\frac{1}{2014}-\frac{1}{2015}\right)}=\frac{1}{5}-\frac{2}{3}=\frac{3}{15}-\frac{10}{15}=-\frac{7}{15}\)
Đúng 0
Bình luận (0)
a, x+1/2017 + x+2/2016 = x+3/2015 + x+4/2014
Mong cac ban giai giup minh voi
\(\frac{x+1}{2017}+\frac{x+2}{2016}=\frac{x+3}{2015}+\frac{x+4}{2014}\)
\(\Leftrightarrow\frac{x+1}{2017}+1+\frac{x+2}{2016}+1=\frac{x+3}{2015}+1+\frac{x+4}{2014}+1\)
\(\Leftrightarrow\frac{x+2018}{2017}+\frac{x+2018}{2016}-\frac{x+2018}{2015}-\frac{x+2018}{2014}=0\)
\(\Leftrightarrow\left(x+2018\right)\left(\frac{1}{2017}+\frac{1}{2016}-\frac{1}{2015}-\frac{1}{2014}\ne0\right)=0\Leftrightarrow x=-2018\)
1. So sanh:
2014×2015-2/2013+2013×2014 voi 2014×2015-1/2014×2015
2. Cho a, b, c thuoc N* va a nho hon b.
Hay chung to: a/b nho hon a+c/b+c va 1 nho hon a/a+b +b/b+c+c/a+c
14 tháng 2 2020 lúc 10:57
Tính các tổng sau:
a) A=1+(-2) + 3 +(-4) + ...+(- 2014) + 2015;
b) B= (-2) + 4 +(-6) + 8 ... +(-2014) + 2016;
c) 1+(-3) + 5 +(-7) + ... + 2013 +(-2015);
d) (-2015) + (-2014) + (-2013)+ ... + 2015 + 2016
\(A=\left[1+\left(-2\right)\right]+\left[3+\left(-4\right)\right]+....+\left[2013+\left(-2014\right)+2015\right]\)
\(A=\left(-1\right)+\left(-1\right)+....+\left(-1\right)+2015\left(\text{1007 số hạng }\left(-1\right)\right)=1008\)
\(B=\left(-2\right)+4+\left(-6\right)+8+\left(-10\right)+,...+\left(-2014\right)+2016\)
\(B=2+2+....+2\left(\text{504 số hạng 2}\right)=1008\)
c) 1 + ( -3 ) +5 + ( -7 ) + ...........+ 2013 + ( -2015 )
[ 1 + (-3 ) ] + [ 5 + -7 ] + .......... + [ 2013 + ( - 2015 ) ]
có số cặp là : [ ( 2015 - 1 ) : 2 + 1 ] : 2 = 504 ( cặp )
= -2 + -2 + -2 +..........+ -2
= -2 x 504
= -1008
Xem thêm câu trả lời
7,5×2013×2014×2015×(3:4-0,75)
Hay giup minh nha mk dang gap
7,5×2013×2014×2015×(3:4-0,75)
=7,5×2013×2014×2015×(0,75-0,75)
=7,5×2013×2014×2015×0
=0
Đúng 0
Bình luận (0)
tính nhanh
A=1+3-5+7-..........-2013+2015
B=1-2+3-4+...................2015-2016
C=1-2-3+4+5-6-6+8+...........+2013-2014-2015+2016
D=1-4+7-10+.....-2014+2017
E=1+2-3-3+5+6 -.......+2013+2014-2015-2016
F=1-2+3-4+..........+2015+2016
G=1+3-5-7+9+11.............-2013-2015
H=1-2-34+5-6-7+8+.................+1013-1014-1015+1016
chị kết bạn với em nha gửi lời kết bn với em nhé
Đúng 0
Bình luận (0)
Tính:
\(\frac{1}{1+\frac{2013}{2014}+\frac{2013}{2015}}+\frac{1}{1+\frac{2014}{2015}+\frac{2014}{2013}}+\frac{1}{1+\frac{2015}{2013}+\frac{2015}{2014}}\)
Tính:
(2014/1+2014/2+2013/3+...+2/2014+1/2015)/(3/2015+3/2014+...+3/2)