<p>5,a,b,5,....</p>
<p>In the sequence above, the first term is 5 and the
second term is a. Each term after the second is the
product of the two immediately preceding terms.
If a < 0, what is the 10th term of the sequence?</p>
<p>(A) -5^21
(B) -5^10
(C) 5
(D) 5^10
(E) 5^21</p>
<p>Im not sure if this is a complete sequence</p>
<p>I just answered this problem on another thread.
8) 5, a, b, 5, …</p>
<p>In the sequence above, the first term is 5 and the second term is a. Each term after the second is the product of the two immediately preceding terms. If A<0, what is the 10th term of the sequence?</p>
<p>(A) -5^21
(B) -5^10
(C) 5
(D) 5^10
(E) 5^21</p>
<p>Solve for a:
b= 5a
5=ab
b=5/a and b= 5a
5/a=5a
5=5a^2
1=a^2
Since a<0, a= -1
5, -1, b, 5
5*(-1)= -5
b= -5
5, a, b, 5, 5b, (5^2)(b), (5^3)(b^2), (5^5)(b^3), (5^8)(b^5), (5^13)(b^8)</p>
<p>Since b= -5, (5^13)((-5)^8) = 5^21</p>
<p>Check <a href=“http://talk.collegeconfidential.com/sat-preparation/1213673-help-problems-released-sats.html[/url]”>http://talk.collegeconfidential.com/sat-preparation/1213673-help-problems-released-sats.html</a></p>