Mấy chế zô giải giùm tui câu này:
Cho \(A=\left(\dfrac{1}{2^2}-1\right)\left(\dfrac{1}{3^2}-1\right)\left(\dfrac{1}{4^2}-1\right).....\left(\dfrac{1}{2013^2}-1\right)\left(\dfrac{1}{2014^2}-1\right)\) và \(B=-\dfrac{1}{2}.\)
Hãy so sánh A và B.
Tính:
a) S=1.2+2.3+3.4+...+99.100
b) B=\(\dfrac{49^{24}.125^{17}.2^8-5^{30}.7^{49}.4^5}{5^{29}.16^2.7^{48}}\)
c) C=\(\left(\dfrac{1}{3}+\dfrac{1}{3^2}+\dfrac{1}{3^3}+\dfrac{1}{3^4}\right).3^5+\left(\dfrac{1}{3^5}+\dfrac{1}{3^6}+\dfrac{1}{3^7}+\dfrac{1}{3^8}\right).3^9+...+\left(\dfrac{1}{3^{97}}+\dfrac{1}{3^{98}}+\dfrac{1}{3^{99}}+\dfrac{1}{3^{100}}\right).3^{101}\)
d) D= \(3-3^2+3^3-3^4+...+3^{2017}-3^{2018}\)
1. Tính:
C= \(\left(\dfrac{1}{2^2-1}\right)\left(\dfrac{1}{3^2-1}\right)\left(\dfrac{1}{4^2-1}\right).....\left(\dfrac{1}{100^2-1}\right)\)
2. Tìm x:
\(\left(\dfrac{2}{5}\right)^x>\left(\dfrac{5}{2}\right)^{-3}.\left(\dfrac{-2}{5}\right)^2\)
Help me!!!
Bài 1:Tính giá trị biểu thức
\(_{1,}\)\(3^2.\dfrac{1}{243}.81^2.\dfrac{1}{3^3}\)
\(_{2,}\)(\(4.2^5\)):\(\left(2^3.\dfrac{1}{16}\right)\)
\(_{3,}\)\(\left(2^{-1}+3^{-1}\right)+\left(2^{-1}.2^0\right):2^3\)
\(_{4,}\)\(\left(-\dfrac{1}{3}\right)^{-1}-\left(-\dfrac{6}{7}\right)^0+\left(\dfrac{1}{2}\right)^2:2\)
\(_{5,}\)[(0,1)\(^2\)]\(^0\)+[(\(\dfrac{1}{7}\))\(^{-1}\)]\(^2\).\(\dfrac{1}{49}.\left[\left(2^2\right)^3:2^5\right]\)
Bài 2:Rút gọn biểu thức
a,\(\dfrac{4^5.9^4-2.6^9}{2^{10}.3^8+6^8.20}\)
b,\(\dfrac{3^6.45^4-15^{13}.5^{-9}}{27^4.25^3+45^6}\)
c,\(\left(\dfrac{2}{5}\right)^7.5^7+\left(\dfrac{9}{4}\right)^3:\left(\dfrac{3}{16}\right)^3\)
\(\overline{2^7.5^2+512}\)
d,\(\left(\dfrac{2}{3}\right)^3.\left(-\dfrac{3}{4}\right)^2.\left(-1\right)^5\)
\(\overline{\left(\dfrac{2}{5}\right)^2}.\left(-\dfrac{5}{12}\right)^3\)
Viết các biểu thức sau dưới dạng lũy thừa
a) \(2^2.9.\dfrac{1}{54}.\left(\dfrac{4}{9}\right)^2\)
b) \(2^3.2^5.\left(\dfrac{3}{2}\right)^4\)
c) \(\dfrac{\left(\dfrac{1}{2}\right)^3.\dfrac{1}{2^2}.8}{\left(-2^3\right)^2.16}.\left(2^2\right)^3\)
Viết các biểu thức sau dưới dạng lũy thừa
a) \(2^2.9.\dfrac{1}{54}.\left(\dfrac{4}{9}\right)^2\)
b) \(2^3.2^5.\left(\dfrac{3}{2}\right)^4\)
c) \(\dfrac{\left(\dfrac{1}{2}\right)^3.\dfrac{1}{2^2}.8}{\left(-2^3\right)^2.16}.\left(2^2\right)^3\)
bài 1 tính
a/ \(\left|1\dfrac{1}{2}-2\dfrac{1}{3}\right|^2+\left|1-\dfrac{5}{4}\right|\)
b/\(\left|\left(-1\right)^{100}-2\dfrac{1}{3}\right|+\dfrac{5}{6}\)
c/\(\left|\left(\dfrac{2}{3}\right)^{-1}-\dfrac{7}{4}\right|-\dfrac{7}{4}\)
d/ \(\left|x-5\right|+\left|x-8\right|\) với 5 \< x>/
Rút gọn biểu thức sau:
B=\(\dfrac{\left(\dfrac{2}{3}\right)^3\times\left(-\dfrac{3}{4}\right)^2\times\left(-1\right)^5}{\left(\dfrac{2}{5}\right)^2\times\left(-\dfrac{5}{12}\right)^3}\)
\(B=\left(\dfrac{1}{2^2}-1\right)\left(\dfrac{1}{3^2}-1\right)\left(\dfrac{1}{4^1}-1\right)\)
