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Ex 5.2, 15 - Chapter 5 Class 10 Arithmetic Progressions
Last updated at Dec. 13, 2024 by Teachoo
Chapter 5 Class 10 Arithmetic Progressions
Concept wise
- Checking if AP or not and finding a, d
- Finding nth term
-
Finding n
- Finding AP
- Finding nth term from end
- Divisible/ multiples
- Statement questions - nth term
- Finding sum of n terms
- Finding number of terms given s
- Given nth term finding s
- Statement questions - Sum of n terms
- Determining AP and finding sum
Transcript
Ex 5.2, 15 For what value of n, are the nth terms of two APs 63, 65, 67,… and 3, 10, 17, … equal Let’s find nth term of both APs 1st AP 63, 65, 67,… We know that an = a + (n – 1) d Here, a = 63 d = 65 – 63 = 2 Putting these in formula an = a + (n – 1) d = 63 + (n – 1) × 2 = 63 + 2n – 2 = 61 + 2n 2nd AP 3, 10, 17 … We know that an = a + (n – 1) d Here, a = 3 d = 10 – 3 = 7 Putting these in formula an = a + (n – 1) d = 3 + (n – 1) 7 = 3 + 7n – 7 = 7n – 4 Given that nth term of 1st AP = nth term of 2nd AP 61 + 2n = 7n – 4 61 + 4 = 7n – 2n 65 = 5n 65/5 = n 13 = n n = 13
