Friday, August 2, 2013

``5th term:` a_2 = 2, a_3 = -sqrt(2)` Find the indicated term of the geometric sequence.

You need to write the following formula such that:


`a_5 = a_1*q^4`


You need to evaluate q and` a_1` , such that:


`a_3 = a_2*q => q = (a_3)/(a_2) => q = (-sqrt2)/2`


`a_2 = a_1*q => a_1 = (a_2)/q => a_1 = 2/((-sqrt2)/2) => a_1 = -2*sqrt2`


You may evaluate `a_5 = a_1*q^4` such that:


`a_5 =  -2*sqrt2*((-sqrt2)/2)^4`


`a_5 =  -2*sqrt2*(4/16) => a_5 = -sqrt2/2`


Hence, evaluating `a_5` yields `a_5 = -sqrt2/2.`

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