Advertisements
Advertisements
प्रश्न
Find the 23rd term of the following A.P.: 9, 4,-1,-6,-11.
Advertisements
उत्तर
9, 4,-1,-6,-11
a = 9 , d = 4 - 9 = -5 , n = 23
tn = a + (n - 1) d
t23 = 9 + (23 - 1)(-5)
= 9 + 22 × -5
= 9 - 110
= -101
APPEARS IN
संबंधित प्रश्न
Find the term t15 of an A.P. : 4, 9, 14, …………..
If the 9th term of an A.P. is zero, then prove that 29th term is double of 19th term.
Find the sum of the following arithmetic series:
`7 + 10 1/2 + 14 + ... + 84`
Decide whether the following sequence is an A.P., if so find the 20th term of the progression:
–12, –5, 2, 9, 16, 23, 30, ..............
Find the 19th term of the following A.P.:
7, 13, 19, 25, ...
Select the correct alternative and write it.
What is the sum of first n natural numbers ?
Select the correct alternative and write it.
If a share is at premium, then -
For a given A.P. a = 3.5, d = 0, then tn = _______.
If the sum of first n terms of an AP is n2, then find its 10th term.
How many multiples of 4 lie between 10 and 205?
Decide whether the given sequence 24, 17, 10, 3,...... is an A.P.? If yes find its common term (tn).
How many two-digit numbers are divisible by 5?
Activity :- Two-digit numbers divisible by 5 are, 10, 15, 20, ......, 95.
Here, d = 5, therefore this sequence is an A.P.
Here, a = 10, d = 5, tn = 95, n = ?
tn = a + (n – 1) `square`
`square` = 10 + (n – 1) × 5
`square` = (n – 1) × 5
`square` = (n – 1)
Therefore n = `square`
There are `square` two-digit numbers divisible by 5.
Decide whether 301 is term of given sequence 5, 11, 17, 23,.....
Activity :- Here, d = `square`, therefore this sequence is an A.P.
a = 5, d = `square`
Let nth term of this A.P. be 301.
tn = a + (n – 1) `square`
301 = 5 + (n – 1) × `square`
301 = 6n – 1
n = `302/6` = `square`
But n is not positive integer.
Therefore, 301 is `square` the term of sequence 5, 11, 17, 23,......
12, 16, 20, 24,...... Find 25th term of this A.P.
If tn = 2n – 5 is the nth term of an A.P., then find its first five terms.
If p - 1, p + 3, 3p - 1 are in AP, then p is equal to ______.
Find a and b so that the numbers a, 7, b, 23 are in A.P.
Write the next two terms of the A.P.: `sqrt(27), sqrt(48), sqrt(75)`......
