Finding nth term

Chapter 5 Class 10 Arithmetic Progressions (Term 2)
Concept wise

This video is only available for Teachoo black users

This video is only available for Teachoo black users

This video is only available for Teachoo black users

This video is only available for Teachoo black users

This video is only available for Teachoo black users

### Transcript

Ex 5.2, 1 Fill in the blanks in the following table, given that a is the first term, d the common difference and an the nth term of the A.P. (i) Here, a = 7 , d = 3 , n = 8 Now, an = a + (n – 1) d Putting values = 7 + (8 – 1) × 3 = 7 + 7 × 3 = 7 + 21 = 28 Ex 5.2, 1 Fill in the blanks in the following table, given that a is the first term, d the common difference and anthe nth term of the A.P. (ii) Here, a = –18 , n = 10 , an = 0 an = a + (n – 1) d Putting values 0 = – 18 + (10 – 1) × d 0 = – 18 + (9) × d 0 + 18 = 9d 18/9 = d 2 = d d = 2 Ex 5.2, 1 Fill in the blanks in the following table, given that a is the first term, d the common difference and an the nth term of the A.P. (iii) Here, d = –3 , n = 18 , an = – 5 Now, an = a + (n – 1) d Putting values –5 = a + (18 – 1) × – 3 –5 = a + 17 × – 3 –5 = a – 51 –5 + 51 = a 46 = a a = 46 Ex 5.2, 1 Fill in the blanks in the following table, given that a is the first term, d the common difference and an the nth term of the A.P. (iv) Here, a = –18.9, d = 2.5 , an = 3.6 Now, an = a + (n – 1) d Putting values 3.6 = –18.9 + (n – 1) × 2.5 3.6 = –18.9 + 2.5 n – 2.5 3.6 = –21.4 + 2.5 n 3.6 + 21.4 = 2.5 n 25 = 2.5 n 25/2.5 = n 10 = n n = 10 Ex 5.2, 1 Fill in the blanks in the following table, given that a is the first term, d the common difference and an the nth term of the A.P. (v) Given a = 3.5, d = 0 , n = 105 Now, an = a + (n – 1) d Putting values = 3.5 + (105 – 1) × 0 = 3.5 + 104 × 0 = 3.5 + 0 = 3.5 Hence, an = 3.5

Made by

#### Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 12 years. He provides courses for Maths and Science at Teachoo.