\(A=\frac{1}{2.5}+\frac{1}{5.8}+\frac{1}{8.11}+...+\frac{1}{92.95}+\frac{1}{95.98}\)
\(A=\frac{1}{3}.\left(\frac{3}{2.5}+\frac{3}{5.8}+\frac{3}{8.11}+...+\frac{3}{92.95}+\frac{3}{95.98}\right)\)
\(A=\frac{1}{3}.\left(\frac{1}{2}-\frac{1}{5}+\frac{1}{5}-\frac{1}{8}+\frac{1}{8}-\frac{1}{11}+...+\frac{1}{92}-\frac{1}{95}+\frac{1}{95}-\frac{1}{98}\right)\)
\(A=\frac{1}{3}.\left(\frac{1}{2}-\frac{1}{98}\right)\)
\(A=\frac{1}{3}.\frac{24}{49}\)
\(A=\frac{8}{49}\)
Vậy ...........
- tính
A = 1/2 x 5 + 1/5 x 8 + 1/8 x 11 +..... + 1/92 x 95 + 1/95 x 98
- ai biết giúp với ;_; tớ cảm ơn ;_;
1/2×5+1/5×8+1/8×11+...+1/92×95+1/95×98
(x-1)/99+(X-2)/98+(X-5)/95=3+1/99+1/98+1/95
Giải từng bước dùm mình nhé
'Mình tick cho
\(A=1/2*5+1/5*8+1/8*11+...+1/92*95+95*98\)
tính: 1/5 + 1/8 + 1/11 +... +1/92 + 1/95
tìm x
a, (x + 9) + (x - 2) + (x + 7) + (x - 4) + (x + 5) + (x - 6) + (x + 3) + (x - 8) + (x + 1) = 95
b, {[(x : 2) - 1/2 ] : 4 - 1/4 } : 5 = 5 + 1/5
Tính nhanh 1/5+1/8+1/11+...+1/92+1/95
tính tổng S=1/5+1/8+1/11+.......+1/92+1/95
tính A =1/5+1/8+...+1/92+1/95
cố giải giúp mình nhé
