第十单元不等式的解法一.选择题.(1)下列不等式中与0)2lg(x同解的是()(A)0)2)(3(xx(B)023xx(C)032xx(D)0)2)(3(xx(2)不等式1)2(logxx的解集是()(A)),2((B)),1((C)(0,1)(D)(0,1)),1((3)不等式022bxax的解集是)31,21(,则a+b的值是()(A)10(B)-10(C)14(D)-14(4)设奇函数f(x)的定义域为[-5,5].若当x∈[0,5]时,f(x)的图象如右图,则不等式f(x)<0的解是()(A)(-5,-2)∪(2,5(B)(-5,-2)∪(2,5)(C)[-2,0]∪(2,5(D)(-2,0)∪(2,5(5)不等式1652xxx的解集是()(A))1,((B)),2((C)35,1(D))35,((6)已知集合M}22|{322xxx,N}0)1(log|{21xx则MN=()(A))23,0((B))2,32((C))2,23((D)(0,1)用心爱心专心(7)在R上定义运算).1(:yxyx若不等式1)()(axax对任意实数x成立,则()(A)11a(B)20a(C)2321a(D)2123a(8)若不等式x2-2ax+a>0,对x∈R恒成立,则关于t的不等式32122tttaa<1的解为()(A)10,x∈(2,5]时,不等式f(x)<0又奇函数f(x)的定义域为[-5,5]故x∈(-2,0),不等式f(x)<0,x∈)2,5[)时,不等式f(x)>05.D[解析]:1652xxx0106516501065222xxxxxxxxx或6.C[解析]:23022322xxxx或可得210)1(log21xx可得故223x7.C[解析]:1)()(axax01,1)1)((22aaxxaxax即任意实数x成立,故0)1(412aa∴2321a8.A[解析]:若不等式x2-2ax+a>0,对x∈R恒成立,则100442aaa又32122tttaa<1,则032122ttt即032321222ttttt∴11时)1()(21)(aaaxfxx的值域用心爱心专心而)1()(21)(aaaxfxx是增函数,故x>1时,)(xf>)(211aa10.C[解析]:设10a,函数)22(log)(2xxaaaxf,若0)(xf则0)22(log2xxaaa,∴1222xxaa∴0)1)(3(xxaa∴xa-3>0,∴x