मराठी

Show that the products of the corresponding terms of the sequences a, ar, ar2, …arn – 1 and A, AR, AR2, … ARn-1 form a G.P, and find the common ratio

Advertisements
Advertisements

प्रश्न

Show that the products of the corresponding terms of the sequences a, ar, ar2, …arn – 1 and A, AR, AR2, … `AR^(n-1)` form a G.P, and find the common ratio

बेरीज
Advertisements

उत्तर

% Sequence a, ar, ar2, …. The sequence formed by the product of arn – 1 and the corresponding terms of A, AR, AR2, .... ARn – 1

`("Second term")/("First term")` = `(arAR)/(aA) = rR`

`("Third term")/("Second term")` = `(ar^2 AR^2)/(arAR) = rR`

Thus, the above sequence forms a G.P. and the common ratio is rR.

shaalaa.com
  या प्रश्नात किंवा उत्तरात काही त्रुटी आहे का?
पाठ 8: Sequences and Series - EXERCISE 8.2 [पृष्ठ १४६]

APPEARS IN

एनसीईआरटी Mathematics [English] Class 11
पाठ 8 Sequences and Series
EXERCISE 8.2 | Q 20. | पृष्ठ १४६

व्हिडिओ ट्यूटोरियलVIEW ALL [1]

संबंधित प्रश्‍न

Find a G.P. for which sum of the first two terms is –4 and the fifth term is 4 times the third term.


Find the sum to n terms of the sequence, 8, 88, 888, 8888… .


if `(a+ bx)/(a - bx) = (b +cx)/(b - cx) = (c + dx)/(c- dx) (x != 0)` then show that a, b, c and d are in G.P.


Which term of the progression 0.004, 0.02, 0.1, ... is 12.5?


Which term of the G.P. :

\[\sqrt{2}, \frac{1}{\sqrt{2}}, \frac{1}{2\sqrt{2}}, \frac{1}{4\sqrt{2}}, . . . \text { is }\frac{1}{512\sqrt{2}}?\]


If the G.P.'s 5, 10, 20, ... and 1280, 640, 320, ... have their nth terms equal, find the value of n.


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


The sum of first three terms of a G.P. is \[\frac{39}{10}\] and their product is 1. Find the common ratio and the terms.

 

The product of three numbers in G.P. is 216. If 2, 8, 6 be added to them, the results are in A.P. Find the numbers.


Find the sum of the following geometric series:

\[\sqrt{2} + \frac{1}{\sqrt{2}} + \frac{1}{2\sqrt{2}} + . . .\text { to 8  terms };\]


Find the sum of the following geometric series:

\[\frac{a}{1 + i} + \frac{a}{(1 + i )^2} + \frac{a}{(1 + i )^3} + . . . + \frac{a}{(1 + i )^n} .\]


Find the sum of the following geometric series:

`sqrt7, sqrt21, 3sqrt7,...` to n terms


Find the sum of the following serie:

5 + 55 + 555 + ... to n terms;


A G.P. consists of an even number of terms. If the sum of all the terms is 5 times the sum of the terms occupying the odd places. Find the common ratio of the G.P.


Prove that: (91/3 . 91/9 . 91/27 ... ∞) = 3.


Find the sum of the terms of an infinite decreasing G.P. in which all the terms are positive, the first term is 4, and the difference between the third and fifth term is equal to 32/81.


Find the rational numbers having the following decimal expansion: 

\[3 . 5\overline 2\]


Show that in an infinite G.P. with common ratio r (|r| < 1), each term bears a constant ratio to the sum of all terms that follow it.


If S denotes the sum of an infinite G.P. S1 denotes the sum of the squares of its terms, then prove that the first term and common ratio are respectively

\[\frac{2S S_1}{S^2 + S_1}\text {  and } \frac{S^2 - S_1}{S^2 + S_1}\]


If a, b, c are in G.P., prove that:

a (b2 + c2) = c (a2 + b2)


If a, b, c are in A.P. and a, b, d are in G.P., then prove that a, a − b, d − c are in G.P.


If pth, qth, rth and sth terms of an A.P. be in G.P., then prove that p − q, q − r, r − s are in G.P.


If a, b, c are in A.P. and a, b, d are in G.P., show that a, (a − b), (d − c) are in G.P.


The sum of two numbers is 6 times their geometric means, show that the numbers are in the ratio `(3+2sqrt2):(3-2sqrt2)`.


If (p + q)th and (p − q)th terms of a G.P. are m and n respectively, then write is pth term.


Write the product of n geometric means between two numbers a and b. 

 


For the G.P. if a = `7/243`, r = 3 find t6.


If for a sequence, tn = `(5^("n"-3))/(2^("n"-3))`, show that the sequence is a G.P. Find its first term and the common ratio


For a G.P. a = 2, r = `-2/3`, find S6


For a G.P. If t4 = 16, t9 = 512, find S10


Find the sum to n terms of the sequence.

0.2, 0.02, 0.002, ...


Select the correct answer from the given alternative.

Which term of the geometric progression 1, 2, 4, 8, ... is 2048


Select the correct answer from the given alternative.

Which of the following is not true, where A, G, H are the AM, GM, HM of a and b respectively. (a, b > 0)


Answer the following:

For a G.P. if t2 = 7, t4 = 1575 find a


Answer the following:

Find `sum_("r" = 1)^"n" (2/3)^"r"`


If x, 2y, 3z are in A.P., where the distinct numbers x, y, z are in G.P. then the common ratio of the G.P. is ______.


If the sum of an infinite GP a, ar, ar2, ar3, ...... . is 15 and the sum of the squares of its each term is 150, then the sum of ar2, ar4, ar6, .... is ______.


The sum of the first three terms of a G.P. is S and their product is 27. Then all such S lie in ______.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×