Q. 13

# The 4th term of a G.P. is square of its second term, and the first term is -3. Find its 7th term.

Answer :

a = -1

T_{4} = (T_{2})^{2}

T_{n} = ar^{n-1}

∴ a.r^{3} = (ar)^{2}

r^{3} = a.r^{2}

⇒ r = a

∴ r =-1

T_{7} = ar^{7-1}

= (-1).r^{6}

= -1.(-1)^{6}

= -1.

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