Odpowiedzi

2009-11-27T23:12:59+01:00
A) an=a1+(n-1)r
r=4 a1=7
55=7+(n-1)*4
55=7+4n-4
52=4n
n=13
b) r=11, a1=121
1100=121+(n-1)11
1100=121+11n-11
1100=110+11n
990=11n
n=90
2 5 2
2009-11-27T23:16:04+01:00
A)
a1 = 7
r=4

an = a1 +(n-1)*r
55 = 7 +(n-1)*4
55 = 4n - 4 + 7
4n = 55 - 3
4n = 52
n = 52 : 4 = 13
Odp.Ten ciag arytmetyczny ma 13 wyrazów.
b)
a1 =121
r = 11
an = a1 +(n - 1)*r
1100 = 121 +(n- 1) * 11
1100 = 121 + 11n -11
11n =1100 -110
11n = 990
n = 990 : 11
n = 90
Odp. ten ciąg arytmetyczny ma 90 wyrazów.
7 5 7
2009-11-27T23:25:50+01:00
A) 7,11,15,19,23,27,31,35,39,43,47,51,51 - 13 wyrazów
b) 121, 132, 143, 154, 165, 176, 187, 198, 209, 220, 231, 242, 254, 265, 276, 287, 298, 309, 320, 331, 342, 353, 364, 375, 386, 397, 408, 419, 430, 441, 452, 463, 474, 485, 496, 507, 518, 529, 540, 551, 562, 573, 584, 595, 606, 617, 628, 639, 650,661, 672, 683, 694, 705, 716, 727, 738, 749, 760, 771, 782, 793, 804, 815, 826, 837, 848, 859, 870, 881, 892, 903, 914, 925, 936, 947, 958, 969, 980, 991, 1002, 1013. 1024, 1035, 1046, 1057, 1068, 1079, 1090, 1101 - 90 wyrazów
3 1 3