geometric-series-b-4-b-7-b-10-b-1-b-3-b-5-2-12-find-b-5-b-2-

Question Number 149424 by mathdanisur last updated on 05/Aug/21

g e o m e t r i c s e r i e s \frac{b_{4} \cdot b_{7} \cdot b_{10}}{b_{1} \cdot b_{3} \cdot b_{5}} = 2^{12}

f i n d \frac{b_{5}}{b_{2}} = ?

Answered by nimnim last updated on 05/Aug/21

b_{n} = {a r}^{n - 1}, t h e n w e h a v e

\frac{{a r}^{3} . {a r}^{6} . {a r}^{9}}{a . {a r}^{2} . {a r}^{4}} = 2^{12} \Rightarrow r^{12} = 2^{12} \Rightarrow r = 2

∴ \frac{b_{5}}{b_{2}} = \frac{{a r}^{4}}{a r} = r^{3} = 2^{3} = 8 ★

Commented by mathdanisur last updated on 05/Aug/21

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