\(x^4-7x^2+1\)
\(=\left(x^2\right)^2-2\cdot\frac{7}{2}\cdot x^2+\left(\frac{7}{2}\right)^2-\frac{45}{4}\)
\(=\left(x^2-\frac{7}{2}\right)^2-\frac{45}{4}\)
mk nghĩ câu này sai đề bài đấy!!!!!!!!!!!
Lưu Thị Thảo Ly
\(x^4-7x^2+1\)
\(=\left(x^2\right)^2-2\cdot\frac{7}{2}\cdot x^2+\left(\frac{7}{2}\right)^2-\frac{45}{4}\)
\(=\left(x^2-\frac{7}{2}\right)^2-\frac{45}{4}\)
mk nghĩ câu này sai đề bài đấy!!!!!!!!!!!
Lưu Thị Thảo Ly
x4+4
x2+2xy+y2-16
3x2+5x-3xy-5y
\(\frac{1}{1-x}.\frac{1}{1+x}.\frac{1}{1+x^2}.\frac{1}{1+x^4}.\frac{1}{1+x^8}.\frac{1}{1+x^{16}}\)
Giups mình nha
Tính: \(\dfrac{1}{3.10}+\dfrac{1}{10.17}+\dfrac{1}{17.24}+...+\dfrac{1}{73.80}-\dfrac{1}{2.9}-\dfrac{1}{9.16}-\dfrac{1}{16.23}-\dfrac{1}{23.30}+\dfrac{1}{1.3}-\dfrac{1}{2.4}+\dfrac{1}{3.5}-\dfrac{1}{3.6}+...+\dfrac{1}{97.99}-\dfrac{1}{98.100}\)
cho S = 1-1/2+1/3-1/4+...-1/2014+1/2015
P = 1/1008+1/1009+...+1/2014+1/2015
tính (S-P)^2016
Cho A = 1+1/2+1/3+..+1/2016
B = 1+1/3+1/5+..+1/4025
so sánh A/B vơis 1+2013/2014
CMR: S=1/(2017+1)+1/(2017+2)+...+1/(3.2017+1)>1
Cho x( 1/y +1/z ) + y( 1/x + 1/z ) + z( 1/x + 1/y ) = -2 và x3+y3+z3 = 1
Tính: A= 1/x + 1/y + 1/z
Rút gọn : \(\left(\frac{1}{1-x}+\frac{1}{1+x}\right)\div\left(\frac{1}{1-x}-\frac{1}{1+x}\right)-\frac{3}{2x}\)
Tính \(A=1+\frac{1}{2}\left(1+2\right)+\frac{1}{3}\left(1+2+3\right)+\frac{1}{4}\left(1+2+3+\text{4}\right)+...+\frac{1}{2016}\left(1+2+...+2016\right)\)
Rút gọn : \(\left(\frac{1+x}{x}+\frac{1}{4x^2}\right)\left(\frac{1-2x}{1+2x}-\frac{1}{1-4x^2}\times\frac{1-4x+4x^2}{1+2x}\right)-\frac{1}{2x}\)