T tmas May 2010 26 0 May 23, 2010 #1 i have no idea how to even attempt a question like this.... Use the two given terms to find a, d, and tn for each arithmetic sequence t5= 16 , t8=25 the answer should be a=4, d=3, tn=3n+1 help?
i have no idea how to even attempt a question like this.... Use the two given terms to find a, d, and tn for each arithmetic sequence t5= 16 , t8=25 the answer should be a=4, d=3, tn=3n+1 help?
Prove It MHF Helper Aug 2008 12,883 4,999 May 23, 2010 #2 tmas said: i have no idea how to even attempt a question like this.... Use the two given terms to find a, d, and tn for each arithmetic sequence t5= 16 , t8=25 the answer should be a=4, d=3, tn=3n+1 help? Click to expand... \(\displaystyle t_8 = t_5 + 3d\) \(\displaystyle 25 = 16 + 3d\) \(\displaystyle 9 = 3d\) \(\displaystyle d = 3\). \(\displaystyle a = t_1 = t_5 - 4d\) \(\displaystyle = 16 - 4(3)\) \(\displaystyle = 4\). Since \(\displaystyle t_n = a + (n - 1)d\) \(\displaystyle t_n = 4 + (n - 1)3\) \(\displaystyle t_n = 4 + 3n - 3\) \(\displaystyle t_n = 3n + 1\). Reactions: HallsofIvy and tmas
tmas said: i have no idea how to even attempt a question like this.... Use the two given terms to find a, d, and tn for each arithmetic sequence t5= 16 , t8=25 the answer should be a=4, d=3, tn=3n+1 help? Click to expand... \(\displaystyle t_8 = t_5 + 3d\) \(\displaystyle 25 = 16 + 3d\) \(\displaystyle 9 = 3d\) \(\displaystyle d = 3\). \(\displaystyle a = t_1 = t_5 - 4d\) \(\displaystyle = 16 - 4(3)\) \(\displaystyle = 4\). Since \(\displaystyle t_n = a + (n - 1)d\) \(\displaystyle t_n = 4 + (n - 1)3\) \(\displaystyle t_n = 4 + 3n - 3\) \(\displaystyle t_n = 3n + 1\).