y=-x^3+15x^2+33x+44y'=-3x^2+30x+33当y'>0时-3x^2+30x+33>0x^2-10x-11<0-1当y'<0时-3x^2+30x+33<0x^2-10x-11>0x>11或 x<-1所以增区间是[-1,11],减区间是(-∞,-1]∪[11,+∞)