rut gon
A=1-6+62-63+...-699+6100
C= 1+6+62+...+6100
C = 1 + 6 + 62+ 63+...+ 6100
6C = 6 + 62+ 63 +...+ 6100 + 6101
6C - C = 6101 - 1
5C = 6101 - 1
C = \(\dfrac{6^{101}-1}{5}\)
\(C=1+6+6^2+...+6^{100}\)
\(\Rightarrow C=\dfrac{6^{100+1}-1}{6-1}\)
\(\Rightarrow C=\dfrac{6^{101}-1}{5}\)
Cho M = 1+6+62+63+...+699
Chứng minh rằng:
a, M chia hết cho 7
b, m chia hết cho 259
62+64+66+...+698+6100
Đặt \(A=6^2+6^4+6^6+...+6^{98}+6^{100}\)
Ta có: \(A=6^2+6^4+6^6+...+6^{98}+6^{100}\)
\(\Leftrightarrow36A=6^4+6^6+...6^{100}+6^{102}\)
\(\Leftrightarrow A-36A=6^2+6^4+6^6+...6^{98}+6^{100}-6^4-6^6-...-6^{100}-6^{102}\)
\(\Leftrightarrow-35\cdot A=6^2-6^{102}\)
\(\Leftrightarrow A=\dfrac{6^{102}-6^2}{35}\)
Cho \(A=(\frac{1}{1-\sqrt{x}}-\frac{1}{\sqrt{x}})\div(\frac{2x+\sqrt{x}-1}{1-x}+\frac{2x\sqrt{x}+x-\sqrt{x}}{1+x\sqrt{x}})\)
a) Rut gonA
b)so sanh Ava\(\sqrt{A}\)
63+65+67+...+699+6101
Đặt \(A=6^3+6^5+6^7+...+6^{99}\)
Ta có: \(A=6^3+6^5+6^7+...+6^{99}\)
\(\Leftrightarrow36\cdot A=6^5+6^7+6^9+...+6^{101}\)
\(\Leftrightarrow A-36A=6^3+6^5+6^7+...+6^{99}-6^5-6^7-6^9-...-6^{101}\)
\(\Leftrightarrow-35\cdot A=6^3-6^{101}\)
\(\Leftrightarrow A=\dfrac{6^{101}-6^3}{35}\)
Điền dấu giữa các số:
1 1 1 = 6 6 6 6 = 6
2 2 2 = 6 7 7 7 = 6
3 3 3 = 6 8 8 8 = 6
4 4 4 = 6 9 9 9 = 6
5 5 5 = 6 10 10 10 = 6
Điền dấu giữa các số:
1 1 1 = 6 6 6 6 = 6
2 2 2 = 6 7 7 7 = 6
3 3 3 = 6 8 8 8 = 6
4 4 4 = 6 9 9 9 = 6
5 5 5 = 6 10 10 10 = 6
rut gon phan so sau:
6*9 -2.17
63*3-119
sao wow hoài vậy bn, ko thấy chán à?
CMR : 1/3+1/5+1/13+1/14+1/15+1/61+1/62+1/63<5/6
CMR : 1/3+1/5+1/13+1/14+1/15+1/61+1/62+1/63 < 5/6