Find an explicit rule for the nth term of a geometric sequence where the second and fifth terms are -12 and 768, respectively.?

Science & Mathematics by Anonymous 2018-06-26 20:35:09

Social Science

2 answers

Find an explicit rule for the nth term of a geometric sequence where the second and fifth terms are -12 and 768, respectively. an = 3 • (-4)^(n + 1) an = 3 • 4^(n - 1) an = 3 • (-4)^(n - 1) an = 3 • 4^n

Anonymous

T(2)=T(1)r=-12-----(1) T(5)=T(1)r^4=786----(2) (2)/(1)=> r^3=-64=> r=-4=> T(1)=-12/(-4)=3 => T(n)=3(-4)^(n-1) Answer.
Anonymous