Chứng minh 5/2+5/6+5/12+5/20+...+5/2450 < 5
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Chứng tỏ: 5/2+5/6+5/12+5/20+5/2450 <5
Giúp mình với ạ, cần gấp
Sửa đề: A=5/2+5/6+...+5/2450
=5(1/2+1/6+...+1/2450)
=5(1-1/2+1/2-1/3+...+1/49-1/50)
=5*49/50<5
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1.Chứng minh rằng: √2 + √6 +√12 + √20 < 12
2. Cho A=1/5+2/(5^2)+3/(5^3)+......+10/(5^10)+11/(5^11). Chứng minh rằng A < 5/16
tính
C=1/2+5/6+11/12+...+2449/2450
C=1-1/2 +1-1/6 +1-1/12 +.............+1-1/2450
=(1+1+1+.........+1)-(1/2 +1/6 +1/12+..............+1/2450)
=49-(1/1.2 +1/2.3 +1/3.4+ ..................+1/49.50)
=49-(1-1/2 +1/2 -1/3+ 1/3- 1/4+............+1/49 -1/50)
=49-(1-1/50) =49-49/50=2401/50
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Thực hiện các phép tính sau một cách hợp lí :
\(\left(\frac{5}{12}+1\frac{4}{3}-0,25\right):\frac{5}{8}+0,15\)
\(\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+........+\frac{1}{2352}+\frac{1}{2450}\)
câu 2:
\(\frac{1}{2}+\frac{1}{6}+...+\frac{1}{2450}\)
\(=\frac{1}{1.2}+\frac{1}{2.3}+...+\frac{1}{49.50}\)
\(=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{49}-\frac{1}{50}\)
\(=1-\frac{1}{50}\)
\(=\frac{49}{50}\)
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lên lời giải hay ý
rg: √(√7−4)2(7−4)2 = 3
chứng minh:
(√8−5√2+√20)√5−(3√110+10)=3.3√10
(√12−6√3+√24)√6(5√12+12)=−14.5√2
bn tuân ơi sao không trả lời cho bn đó đi bn cứ noí những câu linh tinh tự nhiên nói câu như vậy ý như là đi án gái ý
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4 5. 4. 6.
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15 6. 5. 7
3. 4. 2. 5
--- + --- --- + ---
5. 20. 5. 12
4 5. 4. 6.
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15 6. 5. 7
3. 4. 2. 5
--- + --- --- + ---
5. 20. 5. 12
4 5. 4. 6.
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15 6. 5. 7
3. 4. 2. 5
--- + --- --- + ---
5. 20. 5. 12
4 5. 4. 6.
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15 6. 5. 7
3. 4. 2. 5
--- + --- --- + ---
5. 20. 5. 12
4 5. 4. 6.
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15 6. 5. 7
3. 4. 2. 5
--- + --- --- + ---
5. 20. 5. 12
4 5. 4. 6.
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15 6. 5...
Đọc tiếp
4 5. 4. 6.
--- + --- --- + ---
15 6. 5. 7
3. 4. 2. 5
--- + --- --- + ---
5. 20. 5. 12
4 5. 4. 6.
--- + --- --- + ---
15 6. 5. 7
3. 4. 2. 5
--- + --- --- + ---
5. 20. 5. 12
4 5. 4. 6.
--- + --- --- + ---
15 6. 5. 7
3. 4. 2. 5
--- + --- --- + ---
5. 20. 5. 12
4 5. 4. 6.
--- + --- --- + ---
15 6. 5. 7
3. 4. 2. 5
--- + --- --- + ---
5. 20. 5. 12
4 5. 4. 6.
--- + --- --- + ---
15 6. 5. 7
3. 4. 2. 5
--- + --- --- + ---
5. 20. 5. 12
4 5. 4. 6.
--- + --- --- + ---
15 6. 5. 7
3. 4. 2. 5
--- + --- --- + ---
5. 20. 5. 12
4 5. 4. 6.
--- + --- --- + ---
15 6. 5. 7
3. 4. 2. 5
--- + --- --- + ---
5. 20. 5. 12
Khoanh vào phân số lớn hơn 1_3
Chứng minh rằng : A = 5^1+5^2+5^3+...+5^20 chia hết cho 6
A=5^1+5^2+5^3+...+5^20
=(5^1+5^2)+(5^3+5^4)+...+(5^19+5^20)
=(5+5^2)+(5^2.5+5^2+5^2)+...+(5.5^18+5^2+5^18)
=(5^2+5^1).(5^2+...+5^18)
=30.(5^2+...+5^18)
=>Achia hết cho 6
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A=5+52+53+...+520
A=(5+52)+(53+54)+...+(519+520)
A=5.(1+5)+53.(1+5)+...+519.(1+5)
A=5.6+53.6+...519.6
A=6.(5+53+...+519)
Vì: 6⋮6 nên 6.(5+53+...+519)⋮6
Vậy: A⋮6
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cho C=5+5^2+5^3+5^4 ... 5^20. Chứng minh rằng C chia hết cho 5 , 6 , 13
Ta có:
\(C=5+5^2+5^3+...+5^{20}\)
\(=\left(5+5^2+5^3+5^4\right)+\left(5^{17}+5^{18}+5^{19}+5^{20}\right)\)
\(=5.\left(1+5+5^2+5^3\right)+...+5^1\rightarrow7\left(1+5+5^2+5^3\right)\)
\(=5.156+...+5^{17}.156\)
\(=156.\left(5+...+5^{17}\right)=13.12.\left(5+...+5^{17}\right)\)Chia hết cho 5,6,13
Cho C= 5+5^2+5^3+...+5^20. Chứng minh rằng C chia hết cho 6.
ta có :
\(C=\left(5+5^2\right)+\left(5^3+5^4\right)+..+\left(5^{19}+5^{20}\right)\)
\(=5.6+5^3.6+5^5.6+..+5^{19}.6\)
thế nên C chia hết cho 6
C= 5+5^2+5^3+...+5^20.
C=(5+5^2)+(5^3+5^4)...+(5^19+5^20)
C=30+(5^2.5+5^2.5^2)+...+(5^18.5+5^18.5^2)
C=30+5^2.30+...+5^18.30
Vì 30:6 ->30+5^2.30+...+5^18.30->C:6