谢谢 Nicolas2050! 谢谢波斯猫猫!谢谢陆老师!
主帖跟下面的题目有关系。
\(a,b,c,d=正整数, a<b<c<d<90, a+d≠90。\)
\(满足\tan(a^\circ)*\tan(b^\circ)* \tan(c^\circ)*\tan(d^\circ)=1, 这样的数组有多少?\)
谢谢mathe!给出了38组解(计算结果好像还有)。
01: {1, 59, 61, 87}
02: {2, 58, 62, 84}
03: {3, 29, 31, 89}
04: {3, 39, 75, 81}
05: {3, 57, 63, 81}
06: {3, 63, 69, 75}
07: {4, 56, 64, 78}
08: {5, 55, 65, 75}
09: {6, 28, 32, 88}
10: {6, 42, 66, 78}
11: {6, 54, 66, 72}
12: {7, 53, 67, 69}
13: {8, 52, 66, 68}
14: {9, 15, 51, 87}
15: {9, 27, 33, 87}
16: {9, 33, 69, 75}
17: {9, 51, 63, 69}
18: {10, 50, 60, 70}
19: {11, 49, 57, 71}
20: {12, 24, 48, 84}
21: {12, 26, 34, 86}
22: {12, 48, 54, 72}
23: {13, 47, 51, 73}
24: {14, 46, 48, 74}
25: {15, 21, 27, 87}
26: {15, 21, 57, 81}
27: {15, 25, 35, 85}
28: {15, 51, 57, 63}
29: {16, 42, 44, 76}
30: {17, 39, 43, 77}
31: {18, 24, 36, 84}
32: {18, 36, 42, 78}
33: {19, 33, 41, 79}
34: {20, 30, 40, 80}
35: {21, 23, 37, 83}
36: {21, 27, 39, 81}
37: {22, 24, 38, 82}
38: {27, 33, 39, 75} |