tìm x
a ,x-7/4+x-6/3+x-5/3+x+81/7=0
b,x-1/2013+x-2/2012+x+3/2011+...+x-2012/2=2012
c(1/1x101=1/2x102+1/3x103+1/4x164+1/10x110)x X =(1/1x11+1/2x12+...+1/100x110)
ai nhanh mình tick
a) Tính hợp lí các tổng sau:
S1: 1/14+1/35+1/65+.....+1/350
S2: 1/3+1/32+1/33+1/34+.....+1/3300
S3:1/1x3x5+1/3x5x7+1/5x7x9+....+1/25x27x29
S4:1+1/2+1/4+1/8+....+1/1024
b) Tìm x biết
(1/1x101+1/2x102+....+1/10x110)x=1/1x11+1/2x12+...+1/100x110
Cho A = 1/1x101 + 1/2x102 + 1/3x103 + ... + 1/25x125
B = 1/1x26 + 1/2x27 + 1/3x28 + ... + 1/100x125
tìm thương A/B
1/101x1+1/102x2+.....+1/103x3)xX=1/11x1+1/2x12+....+1/100.110
Tính tổng S=(1/2x12 + 1/12x22 +1/22x32 +..........= 1/2002x2012)
Tính nhanh 5/2x1 + 4/1x11 + 3/11x12 + 1/2x15 + 1/2x15 + 13/15x4
tính B=5/21+4/1x11+3/11x2+1/2x15+13/15x4
5/(2x1) + 4/(1x11) + 3/(11x2) + 1/(2x15) + 13/(15x4) = ?
tinh : B=5/2x1 +4/1x11 + 3/11x2 +2/11x2 + 1/2x15 + 13/15x4