The 4th term of a G.P. is square of its second term, and the first term is −3. Determine its 7th term.
Open in App
Verified by Toppr
Let a be the first term and r be the common ratio of the given G.P. ∴a=−3 It is known that, an=arn−1 ∴a4=ar3=(−3)r3 and a2=ar1=(−3)r Now according to the given condition, (−3)r3=[(−3)r]2⇒−3r3=9r2⇒r=−3∴a7=ar7−1=ar6=(−3)(−3)6=−(3)7=−2187 Thus the seventh term of the G.P. is −2187.