H
heodat_15


tìm n biết
1, [TEX]A^2_n -C^{n-1}_{n+1}[/TEX]=4n+6
2,[TEX]C^1_{2n} +C^3_{2n}+C^5_{2n} +... + C^{2n-1}_{2n}[/TEX] = [TEX]2^{23}[/TEX]
1, [TEX]A^2_n -C^{n-1}_{n+1}[/TEX]=4n+6
2,[TEX]C^1_{2n} +C^3_{2n}+C^5_{2n} +... + C^{2n-1}_{2n}[/TEX] = [TEX]2^{23}[/TEX]