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# The 4th Term of a G.P. is Square of Its Second Term, and the First Term is –3. Determine Its 7thterm. - CBSE (Arts) Class 11 - Mathematics

ConceptGeometric Progression (G. P.)

#### Question

The 4th term of a G.P. is square of its second term, and the first term is –3. Determine its 7thterm.

#### Solution

Let a be the first term and r be the common ratio of the G.P.

∴ a = –3

It is known that, an = arn–1

aar3 = (–3) r3

a2 = a r1 = (–3) r

According to the given condition,

(–3) r3 = [­(–3) r]2

⇒ r = –3

a7 = a r 7–1 a r6 = (–3) (–3)6 = – (3)7 = –2187

Thus, the seventh term of the G.P. is –2187.

Is there an error in this question or solution?

#### APPEARS IN

NCERT Solution for Mathematics Textbook for Class 11 (2018 to Current)
Chapter 9: Sequences and Series
Q: 4 | Page no. 192
Solution The 4th Term of a G.P. is Square of Its Second Term, and the First Term is –3. Determine Its 7thterm. Concept: Geometric Progression (G. P.).
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