Advertisements
Advertisements
Question
Find the 23rd term of the following A.P.: 9, 4,-1,-6,-11.
Advertisements
Solution
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
RELATED QUESTIONS
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`
Find the sum of the following arithmetic series:
34 + 32 + 30 + ... + 10
Find the sum of the following arithmetic series:
(–5) + (–8) + (–11) + ... + (–230)
Find the 19th term of the following A.P.:
7, 13, 19, 25, ...
Six year before, the age of mother was equal to the square of her son's age. Three year hence, her age will be thrice the age of her son then. Find the present ages of the mother and son.
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?
Find t5 if a = 3 and d = –3.
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.
If tn = 2n – 5 is the nth term of an A.P., then find its first five terms.
The nth term of an A.P. 5, 8, 11, 14,...... is 68. Find n = ?
In an A.P. if the sum of third and seventh term is zero. Find its 5th term.
What is the formula for the nth (general) term of an arithmetic progression?
According to the pattern of an A.P., how is the term at position \( n \) described in words?
The \( 10^{th} \) term and the \( 18^{th} \) term of an A.P. are \( 25 \) and \( 41 \) respectively. What is the first term \( a \)?
Meera asked for 10 gold coins in the first month, doubling the amount every month. What is Meera's salary in the \( 12^{th} \) month?
