20春华师《初等数论》在线作业

)1:6（A:1B:2C:3D:4正确答案:D(单选)2:(221,391,136)=( ).A:13B:17C:19D:23正确答案:B)3:6x≡18(mod3)解的个数为（A:1B:2C:3D:4个解正确答案:)4:下面的（）12A:0,1，5，11B:C:1，5，7，11D:1，-1，2，-2正确答案:C)5:5（A:-2,-1,0,1,2B:-5,-4,-3,-2,-1C:1,2,3,4,5D:0,1,2,3,4正确答案:D)6:525x+231y=210（A:有解B:无解C:解都是正数D:解都是负数正确答案:A)7:下列关于质数、合数的说法，正确的是（A:两个质数之和一定是质数B:质数一定是奇数C:两个合数之和一定是合数D:两个质数之积一定是合数正确答案:D)8:如果b|a，a|c，则（A:b=cB:C:b|cD:c|b正确答案:C)9:下述结论正确的是（）A:若21x≡70(mod112)，则同余式必有14个解B:同余式5x≡13(mod43)有唯一解x≡37(mod43)C:同余式5x≡13(mod43)有唯一解x=37D:同余式3x≡9(mod15)无解正确答案:C)10:4（A:-2,-1,0,1B:-4,-3,-2,-1C:1,2,3,4D:0,1,2,3正确答案:D)11:下列说法错误的是（A:101B:素数有无限多个C:奇数一定能表示为两平方数之差D:两个连续自然数互质正确答案:A)12:1030（A:4B:5C:6D:7正确答案:C)13:1050858（A:2B:3C:6D:12正确答案:C(单选)14:下列各组数哪一组是模8的完全剩余系（ A:1,3,5,7,9,11,13,15B:2,4,6,8,17,21,23C:-7,-12,-17,-22,-27,-32,-37,-42D:–2,–7,11,15,18,21,24,27正确答案:C)15:1251018（）A:1B:2C:3D:4正确答案:C)16:1577（A:22B:23C:24D:25正确答案:D)17:如果nn(n+1)是（A:奇数B:偶数C:奇数或偶数D:由n正确答案:B)18:n01n23是（）A:1110B:1101C:1011D:1001正确答案:A)19:下列命题中不正确的是（）A:整数a1，a2，…，anB:整数a1，a2，…，anC:整数aD:整数a正确答案:D(单选)20:能被4,5,7整除的最小的正整数是（ ）.A:120B:130C:140D:150正确答案:C)21:3|n7|nA:错误B:正确正确答案:B)22:294194A:错误B:正确正确答案:B)23:111A:错误B:正确正确答案:A)24:存在数m，使ψ(m)A:错误B:正确正确答案:A)25:已知ψ(m)=4，则mA:错误B:正确正确答案:B)26:欧拉函数ψ(480)A:错误B:正确正确答案:B)27:若(a,b)=(a,c),则A:错误B:正确正确答案:A)28:若(a,m)=1，x通过模m的简化剩余系，则ax+b也通过模mA:错误B:正确正确答案:A)29:2009A:错误B:正确正确答案:B)30:5A:错误B:正确正确答案:A)1:6（A:1B:2C:3D:4正确答案:D(单选)2:(221,391,136)=( ).A:13B:17C:19D:23正确答案:B)3:6x≡18(mod3)解的个数为（A:1B:2C:3D:4确答案:)4:下面的（）12A:0,1，5，11B:C:1，5，7，11D:1，-1，2，-2正确答案:C)5:5（A:-2,-1,0,1,2B:-5,-4,-3,-2,-1C:1,2,3,4,5D:0,1,2,3,4正确答案:D)6:525x+231y=210（A:有解B:无解C:解都是正数D:解都是负数正确答案:A)7:下列关于质数、合数的说法，正确的是（A:两个质数之和一定是质数B:质数一定是奇数C:两个合数之和一定是合数D:两个质数之积一定是合数正确答案:D)8:如果b|a，a|c，则（A:b=cB:C:b|cD:c|b正确答案:C)9:下述结论正确的是（）A:21x≡70(mod11214同余式5x≡13(mod43)有唯一解C:5x≡13(mod43)有唯一解x=37D:3x≡9(mod15正确答案:C)10:4（A:-2,-1,0,1B:-4,-3,-2,-1C:1,2,3,4D:0,1,2,3正确答案:D)11:下列说法错误的是（A:101B:素数有无限多个C:奇数一定能表示为两平方数之差D:两个连续自然数互质正确答案:A)12:1030（A:4B:5C:6D:7正确答案:C)13:1050858（A:2B:3C:6D:12正确答案:C(单选)14:下列各组数哪一组是模8的完全剩余系（ A:1,3,5,7,9,11,13,15B:2,4,6,8,17,21,23C:-7,-12,-17,-22,-27,-32,-37,-42D:–2,–7,11,15,18,21,24,27正确答案:C)15:1251018A:1B:2C:3D:4正确答案:C)16:1577（A:22B:23C:24D:25正确答案:D)17:如果nn(n+1)是（A:奇数B:偶数C:奇数或偶数D:由n正确答案:B

）种不同的付法)18:n01n23是（）A:1110B:1101C:1011D:1001正确答案:A)19:下列命题中不正确的是（）A:整数a1，a2，…，anB:整数a1，a2，…，anC:整数aD:整数a与它的绝对值有相同的约数正确答案:D(单选)20:能被4,5,7整除的最小的正整数是（ ）.A:120B:130C:140D:150正确答案:C)21:3|n7|nA:错误B:正确正确答案:B)22:294194A:错误B:正确正确答案:B)23:111A:错误B:正确正确答案:A)24:存在数m，使ψ(m)A:错误B:正确正确答案:A(判断题)25:已知ψ(m)=4，则m可能为5.A:错误B:正确正确答案:B)26:欧拉函数ψ(480)A:错误B: