English

The numbers x − 6, 2x and x2 are in G.P. Find 1st term

Advertisements
Advertisements

Question

The numbers x − 6, 2x and x2 are in G.P. Find 1st term

Sum
Advertisements

Solution

t1 = x – 6

= 10 – 6

= 4

shaalaa.com
  Is there an error in this question or solution?
Chapter 2: Sequences and Series - Exercise 2.1 [Page 28]

APPEARS IN

RELATED QUESTIONS

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


Find the sum to indicated number of terms in the geometric progressions 1, – a, a2, – a3, ... n terms (if a ≠ – 1).


The sum of first three terms of a G.P. is 16 and the sum of the next three terms is 128. Determine the first term, the common ratio and the sum to n terms of the G.P.


Show that the ratio of the sum of first n terms of a G.P. to the sum of terms from (n + 1)th to (2n)th term is `1/r^n`.


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.


If a and b are the roots of are roots of x2 – 3x + p = 0 , and c, d are roots of x2 – 12x + q = 0, where a, b, c, d, form a G.P. Prove that (q + p): (q – p) = 17 : 15.


If a, b, c are in A.P,; b, c, d are in G.P and ` 1/c, 1/d,1/e` are in A.P. prove that a, c, e are in G.P.

 

In a GP the 3rd term is 24 and the 6th term is 192. Find the 10th term.


If the pth and qth terms of a G.P. are q and p, respectively, then show that (p + q)th term is \[\left( \frac{q^p}{p^q} \right)^\frac{1}{p - q}\].


Find three numbers in G.P. whose sum is 38 and their product is 1728.


Find the sum of the following series:

7 + 77 + 777 + ... to n terms;


Find the sum of the following series:

0.6 + 0.66 + 0.666 + .... to n terms


How many terms of the G.P. `3, 3/2, 3/4` ..... are needed to give the sum `3069/512`?


Let an be the nth term of the G.P. of positive numbers.

Let \[\sum^{100}_{n = 1} a_{2n} = \alpha \text { and } \sum^{100}_{n = 1} a_{2n - 1} = \beta,\] such that α ≠ β. Prove that the common ratio of the G.P. is α/β.


Find the sum of the following serie to infinity:

8 +  \[4\sqrt{2}\] + 4 + ... ∞


Find the rational number whose decimal expansion is `0.4bar23`.


If a, b, c, d are in G.P., prove that:

 (a + b + c + d)2 = (a + b)2 + 2 (b + c)2 + (c + d)2


If pth, qth and rth terms of an A.P. and G.P. are both a, b and c respectively, show that \[a^{b - c} b^{c - a} c^{a - b} = 1\]


Find the geometric means of the following pairs of number:

2 and 8


Find the geometric means of the following pairs of number:

−8 and −2


If logxa, ax/2 and logb x are in G.P., then write the value of x.


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

 


If S be the sum, P the product and R be the sum of the reciprocals of n terms of a GP, then P2 is equal to


In a G.P. of even number of terms, the sum of all terms is five times the sum of the odd terms. The common ratio of the G.P. is 


Let x be the A.M. and yz be two G.M.s between two positive numbers. Then, \[\frac{y^3 + z^3}{xyz}\]  is equal to 


For the G.P. if r = `1/3`, a = 9 find t7


For the G.P. if r = − 3 and t6 = 1701, find a.


Which term of the G.P. 5, 25, 125, 625, … is 510?


Mosquitoes are growing at a rate of 10% a year. If there were 200 mosquitoes in the beginning. Write down the number of mosquitoes after n years.


For the following G.P.s, find Sn

0.7, 0.07, 0.007, .....


Find: `sum_("r" = 1)^10(3 xx 2^"r")`


Determine whether the sum to infinity of the following G.P.s exist, if exists find them:

`1/2, 1/4, 1/8, 1/16,...`


Express the following recurring decimal as a rational number:

`0.bar(7)`


Express the following recurring decimal as a rational number:

`2.bar(4)`


Find GM of two positive numbers whose A.M. and H.M. are 75 and 48


Answer the following:

Find three numbers in G.P. such that their sum is 35 and their product is 1000


At the end of each year the value of a certain machine has depreciated by 20% of its value at the beginning of that year. If its initial value was Rs 1250, find the value at the end of 5 years.


The third term of G.P. is 4. The product of its first 5 terms is ______.


Let `{a_n}_(n = 0)^∞` be a sequence such that a0 = a1 = 0 and an+2 = 2an+1 – an + 1 for all n ≥ 0. Then, `sum_(n = 2)^∞ a^n/7^n` is equal to ______.


The sum of infinite number of terms of a decreasing G.P. is 4 and the sum of the terms to m squares of its terms to infinity is `16/3`, then the G.P. is ______.


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×