Multiple choice If \{a_n\} is a geometric sequence with all terms greater than 0, and common ration q\ne 1, then

Multiple choice What is the first term a_1 and the common ratio r of the following geometric sequence if the second, third and fourth terms are: -2, -1, -\dfrac{1}{2} ?

Multiple choice If \{a_n\} is a geometric sequence in which a_4\cdotp a_7=-512 , a_3+a_8=124, and its common ratio q\in Z, then a_{10}= is

Multiple choice If the length of the three sides of a triangle satisfies geometric sequence, determine the range of their common ratio.

Q&A Given the sequence series \{a_n\} satisfies a_1=2 , a_n=3a_{n-1}+1 if n≥2 . If b_n = a_n+\dfrac{1}{2} (1) prove \{b_n\} is a geometric sequence (2) Find the general term formula of \{a_n\}