... cot( Chng minh rng vi mi cp s nguyờn k, n (0 k n 2015) k k +1 k +2 2015 k + 2015 + 2015 = Cnk+ 2015 ta cú: C2015Cn + C2015Cn + C2015Cn + + C2015 Cn Cõu 4.(1,0 im): Tỡm mụun ca s phc z, bit rng ... n dng nh nht cho z1n + z2 = 1015 1015 k 1015 1000 2015 Rỳt gn biu thc : A = C2015 C2015 C2015 C2015 + + (1) k C2015 C2015 + k + + C2015 C2015 Cõu 5.(1,0 im) Trong mt phng vi h ta Oxy, cho ... dx x +1 Cõu 4.(1,0 im) Khai trin P(x) = (x - 2 )2015 thnh dng P = a0 + a1 x + a2 x + + a2015 x 2015 Tớnh h s a2011 v tớnh S = a1+2a2+3a3++2015a2015 T cỏc ch s 0, 1, 2, 6, 7, 8, lp c tt c bao...