TÍNH A=[(1/4*9)+(1/9*14)+(1/14*19)+...+(1/44*49)] x (1-3-5-7-...-49)/89
Tính nhanh:
A=1/6-3/8+7/10-9/11+5/13=11/19-5/13+9/11-7/10+3/8-1/6
A = 9/8 - 8/9 + 3/25 + 1/4 - 5/16 + 19/25 - 1/9 + 2/25 - 1/81
B = -1/3- 8/35 - 2/9 - 1/35 + 4//5 + -4/9 + 3/7
Tính A=3/1^2.2^2 + 5/2^2.2^3 + 7/3^2.4^2 +....+ 19/9^2.10^2
Tính \(A=\left(\frac{1}{4\cdot9}+\frac{1}{9\cdot14}+\frac{1}{14\cdot19}+...+\frac{1}{44\cdot49}\right)\cdot\frac{1-3-5-7-...-49}{89}\)
\(B=\frac{5\cdot4^{15}\cdot9^9-4\cdot3^{20}\cdot8^9}{5\cdot2^{10}\cdot6^{19}-7\cdot2^{29}\cdot27^6}-\frac{2^{19}\cdot27^3+15\cdot4^9\cdot9^4}{6^9\cdot2^{10}+12^{10}}\)
1)Tính :
A= (29+27+1)(223-221+219-217+214-210+29-27+1)
2) Xác định a,b sao cho (x3+ã+b) chia cho (x+1) dư 7, chia (x-3) dư 5
Tính
a) 9/8 - 8/9 = 8/25 + 1/4 - 5/16 + 19/25 - 1/9 + 2/25 - 1/81
b) -1/3 + 4/5 - 8/35 + -2/9 - 1/135 + -4/9 + 3/7
Các bn giải giúp mình nha chiều nay mk phải đi học rùi
Làm chi tiết nha
tính nhanh :
\(B=\frac{1}{3\cdot7}+\frac{1}{7\cdot11}+\frac{1}{11\cdot15}+\frac{1}{15\cdot19}+\frac{1}{19\cdot23}+\frac{1}{23\cdot27}+\frac{1}{27\cdot31}+\frac{1}{31\cdot35}\)
\(A=\frac{1}{3}-\frac{3}{5}+\frac{5}{7}-\frac{7}{9}+\frac{9}{11}-\frac{11}{13}+\frac{13}{15}+\frac{11}{13}-\frac{9}{11}+\frac{7}{9}-\frac{5}{7}+\frac{3}{5}-\frac{1}{3}\)
Tính Hợp Lí:
1/ \(\frac{1}{7}.\frac{1}{3}+\frac{1}{7}.\frac{1}{2}-\frac{1}{7}\)
2/\(\frac{3}{5}.\frac{7}{9}+\frac{3}{5}.\frac{2}{9}+\frac{3}{5}\)
3/ \(21\left(\frac{1}{7}-\frac{1}{5}+\frac{19}{21}\right)\)