Mathematics

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The second term of a G.P is 12 more than the first term,given that the common ratio is half of the first term.find the fourt term of the G.P.

• Mathematics -

ar = a+12
r = a/2

a^2/2 = a+12
a^2 - 2a - 24 = 0
(a-6)(a+4)
so, a=6, r=3
or, a=-4, r=-2

6, 18, 54, 162, ...
or
-4, 8, -16, 32, ...

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