Question

the 4th term of a G.P.is square of its 2nd term and the 1st term is -3. determine its 7th term.

Answer 1

a= -3
a4= (a2)²
We know that
a4=a.r³ & a2=a.r
Therefore
ar³=(a.r)²
(-3).r³=(-3.r)²
-3.r³=9r²
r³/r²=9/-3;
r= -3
Therefore,
a7= a.r power^6
= -3.(-3)power^6
= -3.729
= -2187
Therefore a7 = -2187