=49x50x51
=124950
trên mạng có CM 1 x 2 + 2 x 3 + 3 x 4+ 4 x 5 + ... + n x (n+1) = n x (n+1) x (n+2)
=49x50x51
=124950
trên mạng có CM 1 x 2 + 2 x 3 + 3 x 4+ 4 x 5 + ... + n x (n+1) = n x (n+1) x (n+2)
Tính tổng:
A = 1 x 2 x 3 + 2 x 3 x 4 + 3 x 4 x 5 + ... + 48 x 49 x 50
x . x^2 . x^3 . x^4 . x^5..........x^49 . x^50 = 2024^1275
x.x^2.x^3.x^4.x^5.......x^49.x^50
1/1 x 2 + 1/2 x 3 + 1/3 x 4 + .......
+ 1/49 + 1/50
Tìm x
a) -1/2 . x = 5
b) x-1/9 = 8/3
c) x + 5/6 = 16/42 - -8/56
d) 1 3/4x - 5 = -3 1/3
e) 3 1/3 - 3/4 : x = -1/6
g) 3/x + 5 = 15%
h) 1/2 + 1/2.3 + 1/3.4 +...+1/x(x+1) = 49/50
Tìm x
a) -1/2 . x = 5
b) x-1/9 = 8/3
c) x + 5/6 = 16/42 - -8/56
d) 1 3/4x - 5 = -3 1/3
e) 3 1/3 - 3/4 : x = -1/6
g) 3/x + 5 = 15%
h) 1/2 + 1/2.3 + 1/3.4 +...+1/x(x+1) = 49/50
Cho x1+x2+x3+...+x49+x51=0 và x1+x2=x3+x4=x5+x6=...=x49+x50=x50+x51=1 .Tính x50 = ?
x.x^2.x^3.x^4.x^5.....x^49.x^50