1.tinh bang cach hop li
(1+1/3)*(1+1/9)*(1+1/18)*.......*(1+1/9999)
Tinh bang cach hop li
1/2+1/4+1/8+1/16+1/32
\(A=\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+\frac{1}{32}\)
=> \(2A=1+\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}\)
=> \(2A-A=\left(1+\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}\right)-\left(\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}+\frac{1}{32}\right)\)
=> \(A=1-\frac{1}{32}=\frac{31}{32}\)
tinh bang cach hop li
a, 3/7+2/9+5/9+-9/10
b, 3/4+-1/7+14/7+-6/7+32/28
\(\frac{\frac{1}{9}-\frac{5}{6}-4}{\frac{7}{12}-\frac{1}{36}-10}\)
\(\frac{\frac{1}{9}-\frac{5}{6}-4}{\frac{7}{12}-\frac{1}{36}-10}=\frac{36.\left(\frac{1}{9}-\frac{5}{6}-4\right)}{36.\left(\frac{7}{12}-\frac{1}{36}-10\right)}\)
\(=\frac{4-6.5-36.4}{3.7-1-36.10}\)
\(=\frac{4-30-144}{21-1-360}\)
\(=\frac{-26-144}{20-360}=\frac{-170}{-340}=\frac{1}{2}\)
\(\frac{\frac{4}{36}-\frac{30}{36}-\frac{144}{36}}{\frac{21}{36}-\frac{1}{36}-\frac{360}{36}}=\frac{\frac{-170}{36}}{\frac{-340}{36}}=\frac{-170}{36}:\frac{-340}{36}=\frac{-170}{36}.\frac{36}{-340}=\frac{-170}{-340}=\frac{1}{2}\)
tinh tong bang cach hop li:
a)1/5+1/10+1/20+1/40+..........+1/1280+1/2560
b)1/2+1/6+1/12+...........................+1/90+1/110
tinh bang cach hop li
-1+6+(-11)+16+...+996+(-1001)
\(-1+6+\left(-11\right)+16+....+996+\left(-1001\right)\)
\(=5+5+....+5+5\)
\(=5.10\)
\(=50\)
-1+6+(-11)+16+.....+996+(-1001)
=[-1+6]+[-11+16]+....+[-991+996]+(-1001)
=5 + 5 +...+ 5 + (-1001)
có 100 số 5
=5 x100+(-1001)
=500+(-1001)
=-501
k cho minh nha
chúc bạn học giỏi
tinh bang cach hop li nhat
a ) 1 1/3 * 1 1/4 * 1 1/5 * 1 1/6 * 1 1/7 * 1 1/8 =
b ) 1 1/3 : 1 1/4 : 1 1/5 : 1 1/6 : 1 1/7 : 1 1/8 =
16/27 10000000000000000000000000000000000000000% luon
a) =9/3 = 3
b) 16/27
thông cảm nhé, mình không viết được phân số nên mình viết tạm như vậy !
Tinh bang cach hop li :
1997*1996-1/1995*1997+1996
\(\frac{1997x1996-1}{1995x1997+1996}\)
\(=\frac{1995x1997+1997-1}{1995x1997+1996}\)
\(=\frac{1995x1997+1996}{1995x1997+1996}\)
\(=1\)
tinh bang cach hop li
1/7 + 2/7 + 3/7 + ................. + 3 5/7 + 3 6/7
Ta có: \(\frac{1}{7}+\frac{2}{7}+\frac{3}{7}+...+\frac{35}{7}+\frac{36}{7}=\frac{1+2+3+....+36}{7}\)
\(=\frac{\left(1+36\right)\times36\div2}{7}=\frac{666}{7}=95\frac{1}{7}\)
Vậy giá trị của biểu thức là \(95\frac{1}{7}\)
1/7 + 2/7 + 3/7 + ............... + 35/7 + 36/7 = 666/7
tinh bang cach hop li nếu có thể toán 6
(-1/5+3/12) +-3/4
-1/2+3/21+2/-6+5/-30