tinh nhanh
2016nhân2015-1/2014 nhân 2016+2015
Tinh nhanh phan so
2015 x 2017 - 1 / 2014 + 2015 x 2016
\(2015.2017-\frac{1}{2014}+2015.2016\)
\(=2015.\left(2017+2016\right)-\frac{1}{2014}\)
\(=2015.4033-\frac{1}{2014}\)
\(=8126495\)
Tinh nhanh co ma
Chua phai tinh nhanh dau
Tính nhanh
S=1*2016+2*2015+3*2014+...+2014*3+2015*2+2016*1
Chú thích:"*"là dấu nhân
Viết rõ lới giải nha
1,Tính nhanh
[2015*2015*2014-2014-2014*2015]*[2016*2016+2015*2015*2016]
C= (1/2015+2015/2016)-(1/2017-2014/2015)-(2016/2017-1/2016)
Tinh C.
Giai dum minh voi
Tinh A= 2014/2015+2015/2016+2016/2017+2017/2014 hay so sanh A voi 4
=(2014/2014)+(2015+2015)+(2016/2016)+(2017+2017)
=1+1+1+1
=4
vậy A=4 (4=4)
tinh A/B
A=1/2+1/3+...+1/2016
B=1/2015+2/2014+...+2014/2+2015/1
tính nhanh : ( 2013 x 2014 + 2014 x 2015 + 2015 x 2016 ) x ( 1 + 1/3 - 1 và 1/3 )
( 2013 x 2014 +2014 x 2015 + 2015 x 2016 ) x ( 1 + 1/3 - 1 - 1/3 )
= ( 2013 x 2014 + 2014 x 2015 + 2015 x 2016 ) x 0
= 0
tính nhanh (2015+2014*2016)/(2015*2016-1)
ai nhanh mình k nhưng phải đúng và trình bày nha
\(\frac{2015+2014\cdot2016}{2015\cdot2016-1}\)
\(=\frac{2015+\left(2015-1\right)2016}{2015\cdot2016-1}\)
\(=\frac{2015-2016+2015\cdot2016}{2015\cdot2016-1}\)
\(=\frac{2015\cdot2016-1}{2015\cdot2016-1}\)
\(=1\)
Tinh tong S=1/1×2+1/2×3+1/3×4+...+1/2014×2015+1/2015×2016
\(S=\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+....+\frac{1}{2015.2016}\)
\(S=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+....+\frac{1}{2015}-\frac{1}{2016}\)
\(S=1-\frac{1}{2016}=\frac{2015}{2016}\)
\(S=\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-........+\frac{1}{2015}-\frac{1}{2016}\)
\(S=\frac{1}{1}-\left(-\frac{1}{2}+\frac{1}{2}\right)+\left(-\frac{1}{3}+\frac{1}{3}\right)+......+\left(-\frac{1}{2015}+\frac{1}{2015}\right)-\frac{1}{2016}\)
\(S=\frac{1}{1}-\frac{1}{2016}=\frac{2015}{2016}\)