=1/2 x 2/3 x 3/4 x 4/5 x 5/6 x.....x2013/2014 - 2014/2015
=1/2014 - 2014/2015
=1/2015
=1/2 x 2/3 x 3/4 x 4/5 x 5/6 x.....x2013/2014 - 2014/2015
=1/2014 - 2014/2015
=1/2015
tính nhanh ;
a) (1-1/2)x(1-1/3)x(1-1/4)x....x(1-1/2014)x(1-1/2015)
b) 1/2+1/4+1/8+....+1/256
c) 5/2+5/4+5/8+....+5/256
tính nhanh
a) (1-1/2)x(1-1/3)x(1-1/4)x...x(1-1/2014)x(1-1/2015).
b) 1/2 +1/4+1/8+...+1/256.
c)5/2+5/4+5/8+...+5/256
d)14,35+(13,7-13,6)x1
a = (1 -1/2) x (1-1/3) x (1-1/4) x...x(1-1/2014) x(1-1/2015) = ?
a = (1 -1/2) x (1-1/3) x (1-1/4) x...x(1-1/2014) x(1-1/2015) = ?
Tính tổng: 1 x 2015 + 2 x 2014 + 3 x 2013 + … + 2014 x 2 + 2015 x 1
a)S = 1 + 1/3 + 1/9 + 1/27 + ..................... + 1/2187
b)S = 1 + 1/2 + 1/4 + 1/8 + ..................... + 1/128 + 1/256
c)A = 1 + 2 + 4 + 8 + ..................... + 4096 + 8192
d)1/1 x2 + 1/ 2 x 3 + 1/ 3 x 4 + ................. + 1/ 2013 x 2014
h)A = 1/1 x3 + 1/ 3 x 5 + 1/ 5 x 7 + ................. + 1/ 2013 x 2015
bai2a)1/ 2 x (1 + 2) + 1/ 2 x (1 + 2 + 3) + ............ + 1/2 x (1 + 2 + 3 + ....... + 9)
ai nhanh tick đúng nha
a = (1 -1/2) x (1-1/3) x (1-1/4) x...x(1-1/2014) x(1-1/2015) = ?
cơ hội hiếm
Tính nhanh:
A = (1 - \(\frac{1}{2}\)) x ( 1 - \(\frac{1}{3}\) ) x ( 1 - \(\frac{1}{4}\) ) x ...x ( 1 - \(\frac{1}{2014}\) ) x (1 - \(\frac{1}{2015}\))
tính bằng cách thuận tiện nếu có thể: ( 2013 x 2014 + 2014 x 2015 + 2015 x 2016) x ( 1 + 1/3 - 4/3)