What is the value of m in the given geometric sequence?

[hostergaard]

the sum of the first n terms of an arithmetic sequence {u_n} is given by the
formula s_n=4n²-2n. three terms of this secuence, u₂ u_m and u₃₂ are conscutive terms en a geomtric sequence. find m.

Yea, I am really confused... please help :-)

 

[praharmitra]

you can find tn by

$$u_{n} = s_{n} - s_{n-1}$$

Then find $$u_{m}$$ by applying properties of geometric sequence. work back and find m

 

[HallsofIvy]

In particular, $$u_2= s_2- s_1$$. Find $$s_2$$ and $$s_1$$ from the formula you are given and subtract. $$u_{32}= s_{32}- s_{31}$$. Again find those and subtract. Now you know two terms of a geometric sequence you can find the term between them. $$\frac{u_m}{u_2}= \frac{u_{32}}{u_m}$$.

 

[Diffy]

Helpiamtrappedinatextagandican'tescapefromit!