A=\(\frac{4}{11}-\frac{4}{13}+\frac{4}{13}-\frac{4}{15}+...+\frac{4}{99}-\frac{4}{101}\)
\(A=4\left(\frac{1}{11}-\frac{1}{13}+\frac{1}{13}-\frac{1}{15}+...+\frac{1}{99}-\frac{1}{101}\right)\)
\(A=4.\left(\frac{1}{11}-\frac{1}{101}\right)\)
A=4. 90/1111=360/1111
4/9x11 + 4/11x13 + 4/13X15 + .............+ 4/95X97 + 4/97X99
tính nhannh các tổng sau: G = \(\frac{2}{11x13}\)+ \(\frac{2}{213x15}\) + \(\frac{2}{15x17}\)+ .............+ \(\frac{2}{97x99}\)+ \(\frac{2}{99x101}\)
Tính nhanh tổng sau
2/11x13 + 2/13x15+ 2/97x99
2/11x13 + 2/13x15 + . . . . . . .+2/19x21
vẫn là tính nhanh
\(\frac{2}{1x3}+\frac{2}{3x5}+\frac{2}{5x7}+........+\frac{1}{11x13}+\frac{1}{13x15}\)
ai đúng sẽ k cho người đó
tính nhanh
a) \(\dfrac{5}{7}x\dfrac{3}{2}+\dfrac{3}{2}x\dfrac{9}{7}\)
b)\(\dfrac{4}{5}+\dfrac{4}{5}x6+3x\dfrac{4}{5}\)
sos
Tính Nhanh
a) ( 1/2 + 1/3 + 1/4 + 1/5 + 1/6 ) - ( 1/2 + 1/3 + 1/4 + 1/5 )
b) ( 2/3 + 2/4 + 2/5 + 2/6 + 2/7 ) - ( 2/4 + 2/5 + 2/6 + 2/7 + 28 )
Tính nhanh
a)1/2 x 1/3 + 1/3 x 1/3
b) 1/2 x 4/5 - 1/3 x 4/5
c) 450 x 99 + 456
d) 101 x 101- 101
Gấp ạ!
