\(A=1+2+2^2-2^3+2^4-2^5+...+2^{2016}\)
\(B=\left(1+\frac{8}{10}\right).\left(1+\frac{8}{22}\right).\left(1+\frac{8}{36}\right)...\left(1+\frac{8}{8352}\right)\)
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a) \(A=1-2+2^2-2^3+2^4-2^5+.................+2^{2016}\)
\(\Rightarrow2A=2\left(1-2+2^2-2^3+2^4-2^5+............+2^{2016}\right)\)
\(\Rightarrow2A=2-2^2+2^3-2^4+2^5-2^6+...........+2^{2017}\)
\(\Rightarrow2A-A=\left(2-2^2+2^3-2^4+.........+2^{2016}\right)-\left(1-2+2^3+2^4-2^5+.....+2^{2017}\right)\)\(\Rightarrow A=2^{2017}-1\)
Câu a xong đã, câu b tính sau :P
G=(1+8/10)(1+8/22)(1+8/36)...(1+8/8352)
18.30.44...8360
G=----------------------------
10.22.36...8352
9.2.10.3.11.4...95.88
G=-----------------------------------
10.1.11.2.12.3...96.87
(9.10.11...95)(2.3.4....88)
G= -----------------------------------------
(10.11.12...96)(2.3.4...87)
9.88.
G= ---------= 33/4.
96
A = \(\frac{\frac{3}{4}-\frac{3}{11}+\frac{3}{13}}{\frac{5}{4}-\frac{5}{11}+\frac{5}{13}}+\frac{\frac{1}{2}-\frac{1}{3}+\frac{1}{4}}{\frac{5}{4}-\frac{5}{6}+\frac{5}{8}}\)
\(=\frac{3.\left(\frac{1}{4}-\frac{1}{11}+\frac{1}{13}\right)}{5.\left(\frac{1}{4}-\frac{1}{11}+\frac{1}{13}\right)}+\frac{\frac{1}{2}-\frac{1}{3}+\frac{1}{4}}{\frac{5}{2}.\left(\frac{1}{2}-\frac{1}{3}+\frac{1}{4}\right)}\)
\(=\frac{3}{5}+\frac{1}{\frac{5}{2}}\)
\(=\frac{3}{5}+\frac{2}{5}=1\)
b) B = \(\frac{2^{12}.3^5-4^6.9^2}{\left(2^2.3\right)^6.8^4.3^5}-\frac{5^{10}.7^3:25^5.49}{\left(125.7\right)^3+5^9.14^3}\)
\(=\frac{2^{12}.3^5-\left(2^2\right)^6.\left(3^2\right)^2}{2^{12}.3^6+\left(2^3\right)^4.3^5}-\frac{5^{10}.7^3-\left(5^2\right)^5.7^2}{\left(5^3\right)^3.7^3+5^9.\left(7.2\right)^3}\)
\(=\frac{2^{12}.3^5-2^{12}.3^4}{2^{12}.3^6+2^{12}.3^5}-\frac{5^{10}.7^3-5^{10}-7^2}{5^9.7^3+5^9.7^3.2^3}\)
\(=\frac{2^{12}.3^4.\left(3-1\right)}{2^{12}.3^5\left(3+1\right)}-\frac{5^{10}.7^2.\left(7-1\right)}{5^9.7^3\left(1+2^3\right)}\)
\(=\frac{1}{3.2}-\frac{5.2}{7.3}\)
\(=\frac{7}{3.2.7}-\frac{5.2.2}{7.3.2}\)
\(=\frac{7}{42}-\frac{20}{42}\)
\(=-\frac{13}{42}\)
2A=2+2^2+2^3-2^4+...+2^2017
2A+A=2+1+2^2+2+2^2+2^3-2^3+2^4-2^4+...+2^2017-2^2016
3A=1+2^2+2^3+2^2017
A=(1+2^2+2^3+2^2017)/3
Minh giai 1 bai thoi nha
Nho k cho minh voi