12.82.5【解析】因为0.05+0.15+0.2+0.3=0.7≤0.75,0.05+0.15+0.2+0.3十0.2=0.9>0.75,所以第75百分位数位于区间[80,90)内,所以第75百分位数为80十0.75-0.7=82.5.0.0213.-11]【解析】当x∈(-经,-晋)时,z寸普∈(-罗,0),tan(x+吾)<0,则f(x)=(-1)tan(x+晋),当x∈[-晋)时z+答∈[0,空)tan(x十安}≥6.则f(x)=(m+1)tan(x+,因为f(x)不单调,所以(m+1)(m产25≤0,解得一1≤m≤1,所以m的陬值范围是[-1,1].