tính A biêt
A=(6/8+1)*(6/18+1)*(6/30+1)*...*(6/10700+1)
Tính (6/8+1)(6/18+1)(6/30+1)...(6/10700+1)
1.tính nhanh :(6/8+1).(6/18+1).(6/30+1)...(6/10700+1)
2.chứng minh rằng :A=1/2!+1/3!+1/4!+...+1/1000!
Bài 1.
\(A=\left(\frac{6}{8}+1\right)\left(\frac{6}{18}+1\right)\left(\frac{6}{30}+1\right)...\left(\frac{6}{10700}+1\right)\)
\(A=\frac{14}{8}\times\frac{24}{18}\times\frac{36}{30}\times...\times\frac{10706}{10700}\)
\(A=\frac{2\times7}{1\times8}\times\frac{3\times8}{2\times9}\times\frac{4\times9}{3\times10}\times...\times\frac{101\times106}{100\times107}\)
\(A=\frac{2\times7\times3\times8\times...\times101\times106}{1\times8\times2\times9\times...\times100\times107}\)
\(A=\frac{\left(2\times3\times4\times...\times101\right)\times\left(7\times8\times9\times...\times106\right)}{\left(1\times2\times3\times...\times100\right)\times\left(8\times9\times10\times...\times107\right)}\)
\(A=\frac{101\times7}{107}\)
\(A=\frac{707}{107}\)
Bài 2.
Thiếu đề bài
P/S : bài 1 làm chưa chắc đúng đâu nha.
(6/8+1)(6/18+1)(6/30+1)...(6/10700+1)=?
B=(6/8+1)(6/18+1)(6/30)...(6/10700+1)
Tính nhanh E=\(\frac{6}{8+1}.\frac{6}{18+1}.\frac{6}{30+1}...\frac{6}{10700+1}\)
B=(6/8+1)(6/18+1)(6/30+1)...(6/10700+1)
Tính :
\(A=\left(\frac{6}{8}+1\right)\left(\frac{6}{18}+1\right)\left(\frac{6}{30}+1\right)...\left(\frac{6}{10700}+1\right)\)
Giúp cái !!!
Cho:
D=(6/8+1)*(6/18+1)*(6/30+1)*...*(6/10700+1)
Tính D
Tính nhanh:
F=\(\left(\frac{6}{8}+1\right)\left(\frac{6}{18}+1\right)\left(\frac{6}{30}+1\right).....\left(\frac{6}{10700}+1\right)\)
F=(6/8+1)(6/18+1)(6/30+1)...(6/10700+1)
14.24.36...10706
F= ---------------------------
8.18.30....10700
7.2.8.3.9.4...106.101
F= -----------------------------------
8.1.9.2.10.3...107.100
(7.8.9....106)(2.3.4...101)
F= ----------------------------------------
(8.9.10...107)(2.3.4...100)
7.101
F= ----------
107
F=1
Mình nhầm nhé! Bạn để nguyên:
F =707/101 là được rồi
K mình nhé!