溱潼中学周末作业答案一.填空题1.z=1-3i2.43.4、5.充分不必要条件6.7.332(n41)8.29.;10.②11.12712.62513.18.14..二.解答题15.解:(Ⅰ)数列1na是首项为1,公差为1a的等差数列.(Ⅱ)1naana(Ⅲ)由(1)知:11()nnnnnbaaaaa11()(1)nnaSaaaananana16.解:(1):{x|-10,∴x2+1≥2x,故等号当且仅当x=1时成立.……………………………………………(11分)故当重量比为1∶1时,价值损失的百分率达到最大………………(12分)20解:(1)由函数f(x)图象过点(-1,-6),得m-n=-3,……①由f(x)=x3+mx2+nx-2,得f′(x)=3x2+2mx+n,则g(x)=f′(x)+6x=3x2+(2m+6)x+n;而g(x)图象关于y轴对称,所以-=0,所以m=-3,代入①得n=0.于是f′(x)=3x2-6x=3x(x-2).由f′(x)>得x>2或x<0,故f(x)的单调递增区间是(-∞,0),(2,+∞);由f′(x)<0得0