Tính
a) 1+1/3+1/9+1/27+1/81=.......................................
=
b)37,52+4,7*2.3-9,8=................................
=
TÍNH
A, 1+ 1/3 + 1/9 + 1/27 + 1/81
B, 37,52 +4,7 * 2,3 - 9,8
A = \(1+\frac{1}{3}+\frac{1}{9}+\frac{1}{27}+\frac{1}{81}\)
A = \(\frac{81}{81}+\frac{27}{81}+\frac{9}{81}+\frac{3}{81}+\frac{1}{81}\)
A = \(\frac{81+27+9+3+1}{81}\)
A = \(\frac{121}{81}\)
1 Tinh
a) 1+1/3 +1/9+1/27+1/81.
b) 37,52+4,7 *2,3 - 9,8 .
2 Tim x
a)x: 4,37 = 5,6( du 1,53).
b) 13,5 x (x:5,6) = 36,45
\(1,\)
\(a,1+\frac{1}{3}+\frac{1}{9}+\frac{1}{27}+\frac{1}{81}\)
\(=\frac{81}{81}+\frac{27}{81}+\frac{9}{81}+\frac{3}{81}+\frac{1}{81}\)
\(=\frac{81+27+9+3+1}{81}\)
\(=\frac{121}{81}\)
\(=1\frac{40}{81}\)
\(b,37,25+4,7.2,3-9,8\)
\(=37,25+10,81-9,8\)
\(=38,26\)
\(2,\)
\(a,x:4,37=5,6\left(dư1,53\right)\)
\(x=5,6.4,37+1,53\)
\(\Rightarrow x=26,002\)
\(b,13,5.\left(x:5,6\right)=36,45\)
\(\left(x:5,6\right)=36,45:13,5\)
\(x:5,6=2,7\)
\(x=2,7.5,6\)
\(\Rightarrow x=15,12\)
1.
a . =81/81 + 27/81 + 3/81 + 1/81
= 112/81
b = 37,52 + 10,81 - 9,8
= 48,33 - 9,8
= 38,53
2.
a .x = 5,6 nhân 4,37 +1,53
x=24, 472 + 1,53
x= 26,002
b. x:5,6=36,45:13,5
x :5,6= 2,7
x=2,7 nhân 5,6
x=15,12
1.
1+1/3+1/9+1/27+1/81
=81/81+27/81+3/81+1/81
=112/81
b)37,52+4,7*2,3-9,8
=37,52+10,81-9,8
=48,33-9,8
=38,53
2.
a) x:4,37=5,6(dư 1,53)
x=5,6*4,37+1,53
x=26.002
b) 13,5*(x:5,6)=36,45
x:5,6=36,45/13,5
x:5,6=2,7
x=2,7*5,6
x=15,12
K CHO MÌNH NHA
Tính:
a) 1+\(\frac{1}{3}\)+\(\frac{1}{9}\)+\(\frac{1}{27}\)+\(\frac{1}{81}\)
b)37,52 + 4,7 x 2,3 - 9,8
Ai làm nhanh nhất,mk sẽ tick cho
Giúp mình đi hu...hu
a) Cho: \(A=1+\frac{1}{3}+\frac{1}{9}+\frac{1}{27}+\frac{1}{81}\)
\(\Rightarrow3A=3+1+\frac{1}{3}+\frac{1}{9}+\frac{1}{27}\)
\(\Rightarrow3A-A=3-\frac{1}{81}\)
\(\Rightarrow A=\frac{3-\frac{1}{81}}{2}\)
\(A=\frac{121}{81}\)
b) \(37,52+4,7\times2,3-9,8\)
\(=37,52+10,81-9,8\)
\(=38,53\)
Chúc bn học tốt !!!!!
Tính
1+1/3+/19+1/27+1/81
37,52+4,7×2,3_9,8
bn ơi phép thứ nhất /19 là sao mình ko hiểu
37,52 + 4,7 x 2,3 - 9,8
tính,
37,52+ 4,7* 2,3 -9,8=?
= 38,53 nha bn
Bài 1 tìm x
a) 3/4: x +1/2:1/4=4
b) x +1+1/3+1/9+1/27+1/81 =2
c) x : 25/8-3/4=9/4
d)(15/2.83/10+9/4.83/10+11/2.83/10):x=1126
e)1/1.2+1/2.3+1/3.4+1/4.5+.....+1/(x-1).x=15/16
c)x:25/8-3/4=9/4
x:25/8=9/4+3/4
x:25/8=3
x=3 nhân 25/8
x=75/8
tất cả các bài có người làm rồi li-ke cho mình nha
tính
a) \(log_2\dfrac{1}{16}\)
b) \(log_3243\)
c) \(9^{log_37}\)
d) \(\left(\dfrac{1}{81}\right)^{log_32}\)
a: \(log_2\dfrac{1}{16}=log_22^{-4}=-4\)
b: \(log_3243=log_33^5=5\)
c: \(9^{log_37}=7^{log_39}=7^2=49\)
c: \(\left(\dfrac{1}{81}\right)^{log_32}=\left(3^{-4}\right)^{log_32}=2^{log_33^{-4}}=2^{-4}=\dfrac{1}{16}\)
\(log_2\dfrac{1}{16}=-log_22^4=-4\)
\(log_3243=log_33^5=5\)
\(9^{log_37}=3^{2log_37}=3^{log_349}=49\)
\(\left(\dfrac{1}{81}\right)^{log_32}=3^{-4.log_32}=3^{log_32^{-4}}=2^{-4}=\dfrac{1}{16}\)
Tính
a)\((\dfrac{3}{4}-81).(\dfrac{3^2}{5}-81).(\dfrac{3^3}{6}-81)...(\dfrac{3^{2000}}{2003}-81)\)
b)\(\dfrac{69}{157}-(2+(3+(4+5^{-1})^{-1})^{-1}\)
a: \(\left(\dfrac{3}{4}-81\right)\left(\dfrac{3^2}{5}-81\right)\cdot...\cdot\left(\dfrac{3^{2000}}{2003}-81\right)\)
\(=\left(\dfrac{3^6}{9}-81\right)\left(\dfrac{3}{4}-81\right)\cdot\left(\dfrac{3^2}{5}-81\right)\cdot...\cdot\left(\dfrac{3^{2000}}{2003}-81\right)\)
\(=\left(81-81\right)\left(\dfrac{3}{4}-81\right)\cdot\left(\dfrac{3^2}{5}-81\right)\cdot...\cdot\left(\dfrac{3^{2000}}{2003}-81\right)\)
=0
b: \(\dfrac{69}{157}-\left(2+\left(3+4+5^{-1}\right)^{-1}\right)^{-1}\)
\(=\dfrac{69}{157}-\left(2+\left(3+4+\dfrac{1}{5}\right)^{-1}\right)^{-1}\)
\(=\dfrac{69}{157}-\left(2+1:\dfrac{36}{5}\right)^{-1}\)
\(=\dfrac{69}{157}-\left(2+\dfrac{5}{36}\right)^{-1}\)
\(=\dfrac{69}{157}-\left(\dfrac{77}{36}\right)^{-1}\)
\(=\dfrac{69}{157}-\dfrac{36}{77}=\dfrac{-339}{12089}\)