Chứng minh rằng 1/2 - cho 1/4 + 1/8 - cho 1/16 + 1/32 - 1/6 4 <1/3
chứng minh 1/2 - 1/4 + 1/8 - 1/16 + 1/32 - 1/64 < 1/3
Chứng minh 1/2 + 1/4 + 1/8 + 1/16+ 1/32 + 1/64 < 1/3
Chứng minh: ( 2x + 3y ) Chia hết cho 17 ki và chỉ khi ( 9x + 5y) chia hết cho 17
1 /2 -1 /4 + 1 /8-1 /16 + 1 /32-1 /64 < 1 /3
Cách 1:21/64 < 1/3
Cách 2:21/64 < 0.(3)
Đúng
1 /2 + 1 /4 + 1 /8 + 1 /16 + 1 /32 + 1 /64 < 1 /3
Cách 2:63/64 < 0.(3)
Ko đúng
Câu 3 mình ko biết
a)cho \(\frac{1}{2}-\frac{1}{4}+\frac{1}{8}-\frac{1}{16}+\frac{1}{32}-\frac{1}{64}\)là A
ta có:A=\(\frac{1}{2}-\frac{1}{4}+\frac{1}{8}-\frac{1}{16}+\frac{1}{32}-\frac{1}{64}\)
2A=\(\left(\frac{1}{2}-\frac{1}{4}+\frac{1}{8}-\frac{1}{16}+\frac{1}{32}-\frac{1}{64}\right)2\)
2A=\(1-\frac{1}{2}+\frac{1}{4}-\frac{1}{8}+\frac{1}{16}-\frac{1}{32}\)
2A+A=\(\left(1-\frac{1}{2}+\frac{1}{4}-\frac{1}{8}+\frac{1}{16}-\frac{1}{32}\right)+\left(\frac{1}{2}-\frac{1}{4}+\frac{1}{8}-\frac{1}{16}+\frac{1}{32}-\frac{1}{64}\right)\)
3A=\(1-\frac{1}{64}\Rightarrow3A=\frac{63}{64}\Rightarrow A=\frac{21}{64}< \frac{1}{3}\)
vậy \(\frac{1}{2}-\frac{1}{4}+\frac{1}{8}-\frac{1}{16}+\frac{1}{32}-\frac{1}{64}< \frac{1}{3}\)
b) sai đề (\(\frac{63}{64}< \frac{1}{3}\)hay sao)
c)sai nối (nếu x=y=3 thì 2x+3y=17 chia hết nhưng 9x+5y=42 ko chia hết)
Chứng minh rằng: 1/2-1/4+1/8-1/16+1/32-1/64 <1/3
Đặt A=1/2−1/4+1/8−1/16+1/32−1/64A
=1/2−1/4+1/8−1/16+1/32−1/64
2A=1−1/2+1/4−1/8+1/16−1/32
2A =1−1/2+1/4−1/8+1/16−1/32
3A=2A+A=1−1/64<1
⇒A<1/3
k cho minh nha
Đặt \(A=\frac{1}{2}-\frac{1}{4}+\frac{1}{8}-\frac{1}{16}+\frac{1}{32}-\frac{1}{64}.\)
\(\Rightarrow2A=1-\frac{1}{2}+\frac{1}{4}-\frac{1}{8}+\frac{1}{16}-\frac{1}{32}\)
\(\Rightarrow2A+A=\left(1-\frac{1}{2}+\frac{1}{4}-\frac{1}{8}+\frac{1}{16}-\frac{1}{32}\right)+\left(\frac{1}{2}-\frac{1}{4}+\frac{1}{8}-\frac{1}{16}+\frac{1}{32}-\frac{1}{64}\right)\)
\(\Rightarrow3A=1-\frac{1}{64}< 1\)\(\Rightarrow A< \frac{1}{3}\left(đpcm\right)\)
Vậy \(A< \frac{1}{3}.\)
chứng minh rằng 1/2-1/4+1/8-1/16+1/32-1/64<1/3
đặt A=1/2-1/4+1/8-1/16+1/32-1/64
2A=1-1/2+1/4-1/8+1/16-1/32
2A-A=1-1/64 A=63/64
Vì 63/64<1/3
nên 1/2-1/4+1/8-1/16+1/32-1/64<1/3
Vậy 1/2-1/4+1/8-1/16+1/32-1/64<1/3
chứng minh rằng
1/2-1/4+1/8-1/16+1/32-1/64<1/3
1.Chứng minh rằng a)1/2-1/4+1/8-1/16+1/32-1/64<1/3 b)1/3-2/3^2+3/3^3-4/3^4+...+99/3^99-100/3^100<3/16
Chứng minh rằng :
a)1/2 - 1/4 + 1/8 - 1/16 + 1/32 - 1/64 < 1/3
Ai giúp tui với. Tích cho ai nhanh nhất mà đúng nhé.
Đặt A=1/2−1/4+1/8−1/16+1/32−1/64A=1/2−1/4+1/8−1/16+1/32−1/64
2A=1−1/2+1/4−1/8+1/16−1/322A=1−1/2+1/4−1/8+1/16−1/32
3A=2A+A=1−1/64<1⇒A<1/3
Chứng minh rằng: A< 3
A= 1/2- 1/4+ 1/8- 1/16 +1/32- 1/64
\(A=\left(\frac{1}{2}-\frac{1}{4}\right)+\left(\frac{1}{8}-\frac{1}{16}\right)+\left(\frac{1}{32}-\frac{1}{64}\right)\)
\(A=\frac{1}{4}+\frac{1}{16}+\frac{1}{64}=\frac{21}{64}<\frac{21}{63}\)
\(\Rightarrow A<\frac{21}{63}=\frac{1}{3}\)
AI tích mk mk sẽ tích lại
chứng minh rằng:
B=1/4+1/6+1/8+.......+1/16+1/18<1
chứng minh rằng:
C=1/4+1/5+1/6+........+1/14+1/15
toán chọn lọc lớp 4
Chứng minh rằng: A>B khi:
A=(3+1)(3^2+1)(3^4+1)(3^6+1)(3^8+1)(3^16+1) B=3^32 -1