Advertisements
Advertisements
प्रश्न
If the 9th term of an A.P. is zero then show that the 29th term is twice the 19th term?
Advertisements
उत्तर
It is given that,
t9 = 0
Now,
tn = a + (n - 1)d
t9 = a + (9 - 1)d
⇒ 0 = a + 8d
⇒ a = -8d ...(1)
t29 = a + (29 - 1)d
= -8d + 28d
= 20d ...(2)
t19 = a + (19 - 1)d
= -8d + 18d
= 10d ...(3)
From (2) and (3), we get
t29 = 2t19
Hence, the 29th term is twice the 19th term.
APPEARS IN
संबंधित प्रश्न
The ratio of the sum use of n terms of two A.P.’s is (7n + 1) : (4n + 27). Find the ratio of their mth terms
200 logs are stacked in the following manner: 20 logs in the bottom row, 19 in the next row, 18 in the row next to it and so on. In how many rows are the 200 logs placed, and how many logs are in the top row?
Find the sum of the following arithmetic progressions:
−26, −24, −22, …. to 36 terms
If numbers n – 2, 4n – 1 and 5n + 2 are in A.P., find the value of n and its next two terms.
The 9th term of an AP is -32 and the sum of its 11th and 13th terms is -94. Find the common difference of the AP.
If 18, a, (b - 3) are in AP, then find the value of (2a – b)
Draw a triangle PQR in which QR = 6 cm, PQ = 5 cm and times the corresponding sides of ΔPQR?
If the sum of P terms of an A.P. is q and the sum of q terms is p, then the sum of p + q terms will be
If Sn denote the sum of n terms of an A.P. with first term a and common difference dsuch that \[\frac{Sx}{Skx}\] is independent of x, then
The common difference of the A.P.
Let the four terms of the AP be a − 3d, a − d, a + d and a + 3d. find A.P.
Suppose three parts of 207 are (a − d), a , (a + d) such that , (a + d) >a > (a − d).
In an A.P., the sum of its first n terms is 6n – n². Find is 25th term.
Find the sum of odd natural numbers from 1 to 101
In an AP if a = 1, an = 20 and Sn = 399, then n is ______.
Sum of 1 to n natural number is 45, then find the value of n.
Find the sum of first 25 terms of the A.P. whose nth term is given by an = 5 + 6n. Also, find the ratio of 20th term to 45th term.
Which term of the Arithmetic Progression (A.P.) 15, 30, 45, 60...... is 300?
Hence find the sum of all the terms of the Arithmetic Progression (A.P.)
The sum of A.P. 4, 7, 10, 13, ........ upto 20 terms is ______.
