Sunday, October 12, 2014

``7th term:` 3, 36, 432...` Find the indicated term of the geometric sequence.

You may use the following formula, such that:


`a_n = a_1*r^(n-1)` ` `


Replacing 7 for n, 3 for `a_1` yields:


`a_7 = 3*(r)^6`


You may find the ratio r, such that:


`r = (a_2)/(a_1) => r = 36/3 => r = 12`


`a_7 = 3*(12)^6 => a_7 = 3*(3*4)^6 => a_7 = 3^7*4^6`


Hence, the indicated term `a_7` is` a_7 =3^7*4^6.`

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