Tính nhanh :
1)A=\(\frac{1}{2}-\frac{1}{2^2}+\frac{1}{2^3}-...+\frac{1}{2^{99}}-\frac{1}{2^{100}}\)
2)B=\(\frac{1}{2}+\frac{1}{2^3}+\frac{1}{2^5}+...+\frac{1}{2^{99}}\)
3)C=\(\frac{1}{2}-\frac{1}{2^4}+\frac{1}{2^7}-\frac{1}{2^{10}}+...-\frac{1}{2^{58}}\)
Cho Sn=1-2+3-4+...+(-1)n-1.n với n=1,2,3,...
Tính S35+S60
a,\(\frac{-1}{24}-\left[\frac{1}{4}-\left(\frac{1}{2}-\frac{7}{8}\right)\right]\)
b,\(\left[\frac{5}{7}-\frac{7}{5}\right]-\left[\frac{1}{2}-\left(\frac{-2}{7}-\frac{1}{10}\right)\right]\)
c,\(\left(\frac{-1}{2}\right)-\left(\frac{-3}{5}\right)+\left(\frac{-1}{9}\right)+\frac{1}{71}-\left(\frac{-2}{7}\right)+\frac{4}{35}-\frac{7}{8}\)
d,\(\left(3-\frac{1}{4}+\frac{2}{3}\right)-\left(5-\frac{1}{3}-\frac{6}{5}\right)-\left(6-\frac{7}{4}+\frac{3}{2}\right)\)
e,\(\left(\frac{1}{2}-\frac{13}{14}\right):\frac{5}{7}-\left(\frac{-2}{21}+\frac{1}{7}\right):\frac{5}{7}\)
g,\(\frac{4}{9}:\left(\frac{-1}{7}\right)+6\frac{5}{9}:\left(\frac{-1}{7}\right)\)
Bài 1: Tìm x, biết
\(a,\frac{2}{3}-\frac{1}{3}.\left(x-\frac{3}{2}\right)-\frac{1}{2}.\left(2x+1\right)=5\)
\(b,\left(x+\frac{1}{2}\right).\left(x-\frac{3}{4}\right)=0\)
\(c,\left(2x-5\right)^4=81\)
\(d,3^{x+1}+3^{x+3}=810\)
bài 2
q,\(\frac{11}{3}-\left(\frac{5}{42}-x\right)\)
b,\(x+\frac{1}{3}=\frac{2}{5}-\left(\frac{-1}{3}\right)\)
c,\(\frac{-2}{3}x+\frac{5}{7}=\frac{3}{10}\)
d,\(\frac{3}{7}-x=\frac{1}{4}-\left(\frac{-3}{5}\right)\)
Bài 1: So sánh: a) (\(\frac{1}{2}\))\(^2\) và (\(\frac{1}{2}\))\(^5\) b) (2,4)\(^3\) và (2,4)\(^2\) c) (-1\(\frac{1}{2}\))\(^2\) và (-1\(\frac{1}{2}\))\(^3\) d) 2\(^{225}\) và 3\(^{150}\)
Bài 2: Tính: a) 25\(^3\) : 5\(^2\) b) (\(\frac{3}{7}\))\(^{21}\) : (\(\frac{9}{49}\))\(^6\) c) 3- (-\(\frac{6}{7}\))\(^0\) + (\(\frac{1}{2}\))\(^2\):2 d) 9.3\(^3\).\(\frac{1}{81}\).3\(^2\) e) 4.2\(^5\): (2\(^3\).\(\frac{1}{16}\)) g) 3\(^2\).2\(^5\).(\(\frac{2}{3}\))\(^2\) h) (\(\frac{1}{3}\))\(^2\).\(\frac{1}{3}\).9\(^2\)
Gúp mk vs, mk cần gấp ạ
Tính giá trị biểu thức
\(\left(\frac{2}{5}-\frac{1}{2}\right)^2+\left(\frac{1}{2}+\frac{3}{5}\right)^2\)
Tìm x
\(1.\left(x+0,7\right)^3=-27\)
\(2.\left(2x-1\right)^{10}=49^5\)
\(3.\left(\frac{2}{3}x-\frac{1}{3}\right)^5=\frac{1}{243}\)
\(4.\left(\frac{2}{5}-3x\right)^2=\frac{9}{25}\)
CÁC BẠN GIÚP MÌNH VỚI !!!!!
a,\(\frac{2}{3}-4.\left(\frac{1}{2}+\frac{3}{4}\right)\)
b,\(\left(\frac{-1}{3}+\frac{5}{6}\right).11-7\)
c,\(\left(\frac{-5}{9}\right).\frac{3}{11}+\left(\frac{-13}{18}\right).\frac{3}{11}\)
d,\(\left(\frac{-2}{3}\right).\frac{3}{11}+\left(\frac{-13}{18}\right).\frac{3}{11}\)
giúp mình với làm ơn