Advertisements
Advertisements
Question
Complete the following activity to find the 19th term of an A.P. 7, 13, 19, 25, ........ :
Activity:
Given A.P. : 7, 13, 19, 25, ..........
Here first term a = 7; t19 = ?
tn + a + `(square)`d .........(formula)
∴ t19 = 7 + (19 – 1) `square`
∴ t19 = 7 + `square`
∴ t19 = `square`
Advertisements
Solution
Given, A.P. : 7, 13, 19, 25, ..........
Here, first term a = 7; t19 = ?
tn + a + (n – 1)d .........(formula)
∴ t19 = 7 + (19 – 1)6
∴ t19 = 7 + 108
∴ t19 = 115
APPEARS IN
RELATED QUESTIONS
If the sum of the first n terms of an AP is 4n − n2, what is the first term (that is, S1)? What is the sum of the first two terms? What is the second term? Similarly, find the 3rd, the 10th, and the nth terms.
Find the sum of the first 11 terms of the A.P : 2, 6, 10, 14, ...
The 8th term of an AP is zero. Prove that its 38th term is triple its 18th term.
If 4 times the 4th term of an A.P. is equal to 18 times its 18th term, then find its 22nd term.
If the sum of first m terms of an AP is ( 2m2 + 3m) then what is its second term?
Write an A.P. whose first term is a and common difference is d in the following.
Kargil’s temperature was recorded in a week from Monday to Saturday. All readings were in A.P. The sum of temperatures of Monday and Saturday was 5°C more than sum of temperatures of Tuesday and Saturday. If temperature of Wednesday was –30° celsius then find the temperature on the other five days.
The Sum of first five multiples of 3 is ______.
In an A.P. the first term is 8, nth term is 33 and the sum to first n terms is 123. Find n and d, the common differences.
In a school, students decided to plant trees in and around the school to reduce air pollution. It was decided that the number of trees, that each section of each class will plant, will be double of the class in which they are studying. If there are 1 to 12 classes in the school and each class has two sections, find how many trees were planted by the students.
If in an A.P. Sn = n2p and Sm = m2p, where Sr denotes the sum of r terms of the A.P., then Sp is equal to
The sum of n terms of an A.P. is 3n2 + 5n, then 164 is its
Suppose three parts of 207 are (a − d), a , (a + d) such that , (a + d) >a > (a − d).
In an A.P. sum of three consecutive terms is 27 and their products is 504. Find the terms. (Assume that three consecutive terms in an A.P. are a – d, a, a + d.)
What is the sum of an odd numbers between 1 to 50?
The sum of the first 15 multiples of 8 is ______.
The sum of the first five terms of an AP and the sum of the first seven terms of the same AP is 167. If the sum of the first ten terms of this AP is 235, find the sum of its first twenty terms.
Show that the sum of an AP whose first term is a, the second term b and the last term c, is equal to `((a + c)(b + c - 2a))/(2(b - a))`
Find the sum of first 'n' even natural numbers.
