2cos²x+cos5x=3

\(S=\left(C^1_{2018}\right)^2+2\left(C_{2018}^2\right)^2+...+2018\left(C_{2018}^{2018}\right)^2\)

Tính tổng

\(P=\frac{2017}{A^0_{2017}}+\frac{2016}{A^1_{2017}}+...+\frac{2}{A^{2015}_{2017}}+\frac{1}{A_{2017}^{2016}}\)

tính

\(m^2+n^2+p^2+q^2+1\ge m\left(n+p+q+1\right)\)

\(x^2+y^2+z^2+3\ge2\left(x+y+z\right)\)

co bao nhieu cach phan cong 8 hoc sinh thanh 2 nhom: 1 nhóm co 5 ban, nhom kia co 3 ban

\(\left\{{}\begin{matrix}x^2-3x=y\\y^2-3y=x\end{matrix}\right.\)