a) 1/3 + 1/12 +1/48 +1/192 +.... +1/36864
b) 1 + 1/5 + 1/ 25 +1 / 125 +.... 1 /78125
GIẢI HỘ MK NHA
a) A=1+1/5+1/25+1/125+1/625+...+1/78125
b)B=1/3+1/12+1/48+1/192+1/768+...+1/36864
c)C=5/3+5/6+5/12+5/24...+5/192+5/384
GIÚP MÌNH VỚI XIN MỌI NGƯỜI AI GIÚP MÌNH THÌ MÌNH CHO TICK LÀM TẤT CẢ MỌI THỨ
\(1+\frac{1}{5}+\frac{1}{25}+\frac{1}{125}+\frac{1}{625}+.......+\frac{1}{78125}\)
tính hộ nha
Tính nhanh:
a) A= 1 + \(\dfrac{1}{5}+\dfrac{1}{25}+\dfrac{1}{125}+\dfrac{1}{625}+...+\dfrac{1}{78125}\)
b) B= \(\dfrac{1}{3}+\dfrac{1}{12}+\dfrac{1}{48}+\dfrac{1}{192}+\dfrac{1}{768}+...+\dfrac{1}{36864}\)
c) M= \(\dfrac{1}{3}+\dfrac{1}{6}+\dfrac{1}{12}+\dfrac{1}{20}+\dfrac{1}{30}+...+\dfrac{1}{9900}\)
d) P= \(\dfrac{1}{1+2}+\dfrac{1}{1+2+3}+\dfrac{1}{1+2+3+4}+...+\dfrac{1}{1+2+3+4+...+2018}\)
1,thực hiện phép tính bằng cách thuận tiện nhất
a,1 + \(\dfrac{1}{5}+\dfrac{1}{25}+\dfrac{1}{125}+\dfrac{1}{625}+...+\dfrac{1}{78125}\)
\(A=1+\dfrac{1}{5}+\dfrac{1}{25}+\dfrac{1}{125}+...+\dfrac{1}{625}+\dfrac{1}{78125}\)
\(=1+\dfrac{1}{5}+\dfrac{1}{5^2}+\dfrac{1}{5^3}+...+\dfrac{1}{5^7}\)
\(5A=5+1+\dfrac{1}{5}+\dfrac{1}{5^2}+...+\dfrac{1}{5^6}\)
\(\Leftrightarrow5A-A=5+1+\dfrac{1}{5}+\dfrac{1}{5^2}+...+\dfrac{1}{5^6}-1-\dfrac{1}{5}-\dfrac{1}{5^2}-\dfrac{1}{5^3}-...-\dfrac{1}{5^7}\)
\(\Leftrightarrow4A=5-\dfrac{1}{5^7}\Leftrightarrow A=\dfrac{5-\dfrac{1}{5^7}}{4}=\dfrac{\dfrac{390624}{78125}}{4}=\dfrac{390624}{312500}=\dfrac{97656}{78125}\)
a) 1/100.99 - 1/99.98 - 1/98.97 - ........... - 1/3.2 - 1/2.1
b) (1+2+3+.........+100) . (1/3-1/5-1/7-1/9) . (6,3.12-21.3,6)/1/2+1/3+1/4+......+1/100
c)1/4-1/7-1/11phan4/4-4/7-4/11+3/5-3/15-3/125-3/625phan4/5-4/25-4/125-4/625
giải ra hộ mk nha
Tính 1 cách hợp lí :
1+ 1/5 + 1/25 + 1/125 + 1/625 +........+ 1/78125
\(A=1+\frac{1}{5}+\frac{1}{25}+...+\frac{1}{78125}\)
\(5A=5+1+\frac{1}{5}+\frac{1}{25}+...+\frac{1}{15625}\)
\(\left(5A-A\right)=\left(5+1+\frac{1}{5}+...+\frac{1}{15625}\right)-\left(1+\frac{1}{5}+...+\frac{1}{78125}\right)\)
\(4A=5-\frac{1}{78125}\)
\(A=5-\frac{1}{312500}\)
a,1 + 1/5 + 1/25 + 1/125 + 1/625
b,1/3 + 1/6 + 1/12 + 1/24 + 1/48 + 1/96
BÀI TÍNH NHANH
A.2/3+2/6+2/12+2/24+2/48+2/96+2/192
B.1/2+1/4+1/8+1/16+1/32+1/64+1/128+1/256
C.1/3+1/9+1/27+1/81+1/243+1/729
D.3/2+3/8+3/32+3/128+3/512
E.3+3/5+3/25+3/125+3/625
a) = \(\frac{127}{96}\)
b) = \(\frac{255}{256}\)
c) Mik bỏ nha
d) = \(\frac{1023}{512}\)
e) = \(\frac{2343}{625}\)
bài 6: TÍNH NHANH NÂNG CAO LỚP 5
A= 1/5+1/25+1/125+1/625+1/3125
giải hộ mình nhanh nhanh nha các bạn
5A=(1/5+1/25+1/125+1/625+1/3125)*5
5A=(1+1/5+1/25+1/125+1/625)
5A-A=(1+1/5+1/25+1/125+1/625)-(1/5+1/25+1/125+1/625+1/3125)=1-1/3125
4A=1-1/3125=3124/3125
A=3124/3125:4=781/3125.