matematykaszkolna.pl
ewelina BLAGA POMOZCIE TO NA JUTRO!!!!!!!!!!!: Wyznacz wzor na n-ty wyraz iagu, ktorego suma n poczatkowych wyracow wyraza sie wzorem: a) Sn= 3n2-n b)Sn-n2-4n c)Sn=5n-n2 1 1 d)Sn= ----- n - ---- n2 2 4
5 sty 20:30
%3Cpre%3E%3Cb%3Eewelina%20BLAGA%20POMOZCIE%20TO%20NA%20JUTRO!!!!!!!!!!!%3A%3C%2Fb%3E%20pomoocyyyyyyyyy%3Cimg%20style%3D%22margin-bottom%3A-3px%22%20src%3D%22emots%2F2%2Fwykrzyknik.gif%22%3E%3Cimg%20style%3D%22margin-bottom%3A-3px%22%20src%3D%22emots%2F2%2Fwykrzyknik.gif%22%3E%3Cimg%20style%3D%22margin-bottom%3A-3px%22%20src%3D%22emots%2F2%2Fwykrzyknik.gif%22%3E%3Cimg%20style%3D%22margin-bottom%3A-3px%22%20src%3D%22emots%2F2%2Fwykrzyknik.gif%22%3E%3Cimg%20style%3D%22margin-bottom%3A-3px%22%20src%3D%22emots%2F2%2Fwykrzyknik.gif%22%3E%3Cimg%20style%3D%22margin-bottom%3A-3px%22%20src%3D%22emots%2F2%2Fwykrzyknik.gif%22%3E%3Cimg%20style%3D%22margin-bottom%3A-3px%22%20src%3D%22emots%2F2%2Fwykrzyknik.gif%22%3E%3Cimg%20style%3D%22margin-bottom%3A-3px%22%20src%3D%22emots%2F2%2Fwykrzyknik.gif%22%3E%3Cimg%20style%3D%22margin-bottom%3A-3px%22%20src%3D%22emots%2F2%2Fwykrzyknik.gif%22%3E%3Cimg%20style%3D%22margin-bottom%3A-3px%22%20src%3D%22emots%2F2%2Fwykrzyknik.gif%22%3E%3Cimg%20style%3D%22margin-bottom%3A-3px%22%20src%3D%22emots%2F2%2Fwykrzyknik.gif%22%3E%3Cimg%20style%3D%22margin-bottom%3A-3px%22%20src%3D%22emots%2F2%2Fwykrzyknik.gif%22%3E%3Cimg%20style%3D%22margin-bottom%3A-3px%22%20src%3D%22emots%2F2%2Fwykrzyknik.gif%22%3E%3Cimg%20style%3D%22margin-bottom%3A-3px%22%20src%3D%22emots%2F2%2Fwykrzyknik.gif%22%3E%3Cimg%20style%3D%22margin-bottom%3A-3px%22%20src%3D%22emots%2F2%2Fwykrzyknik.gif%22%3E%3Cimg%20style%3D%22margin-bottom%3A-3px%22%20src%3D%22emots%2F2%2Fwykrzyknik.gif%22%3E%3Cimg%20style%3D%22margin-bottom%3A-3px%22%20src%3D%22emots%2F2%2Fwykrzyknik.gif%22%3E%3Cimg%20style%3D%22margin-bottom%3A-3px%22%20src%3D%22emots%2F2%2Fwykrzyknik.gif%22%3E%0A%3C%2Fpre%3E
5 sty 21:32
ewelina BLAGA POMOZCIE TO NA JUTRO!!!!!!!!!!!: pomoocyyyyyyyyyemotikonka
5 sty 21:32
danaole: ale jaki to ciąh
5 sty 21:42
ewelina BLAGA POMOZCIE TO NA JUTRO!!!!!!!!!!!: arytmetyczny
5 sty 21:48
%3Cpre%3E%3Cb%3Eewelina%20BLAGA%20POMOZCIE%20TO%20NA%20JUTRO!!!!!!!!!!!%3A%3C%2Fb%3E%20arytmetyczny%0A%3C%2Fpre%3E
5 sty 21:48
Eta: można tak! a1= S1= 3*1-1= 2 S2= 3*22 -2= 12-2=10 to oznacza że a2 = 10-2=8 to r= 6 an= a1 +(n-1)*r an= 2 +(n-1)*6 = 6n -4
5 sty 21:50
Eta: Widać,że 1/ to arytmetyczny!
5 sty 21:51
nalepek: A) lub tak: Sn=3n2-n Sn-1=3(n-1)2-(n-1) Sn-1=3n2-6n+3-n+1 Sn-1=3n2-7n+4 an=Sn-Sn-1 an=3n2-n-3n2+7n-4 an=6n-4
5 sty 21:54
Eta: W b) zapisz porzadnie bo nie napisalas znaku = i nie wiem czy = - w c) podobnie jak w a) S1= 5-1=4 to a1=4 S2= 10-4= 6 to a2 = 4- 6= -2 S3= 15-9=6 to a3=0 wiec juz widac ,że to ciag arytm . a1=4 r = -2 czyli an= A1 +(n-1)*r = 4 +(n-1)*(-2) = -2n +6 sprawdzenie; Sn= (a1 +an)/2 * n Sn =(4 -2n +6)/2* n = ( -2n2 +10n)/2= - n2 +5n = 5n -n2 czyli ok!
5 sty 22:00
Eta: Też tak można Nalepek!emotikonka
5 sty 22:01
ewelina BLAGA POMOZCIE TO NA JUTRO!!!!!!!!!!!: w b) jest tam =
8 sty 18:59