Math, asked by npacharia8679, 9 months ago

The sum of n terms of an ap is n2-n , then the nth term will be

Answers

Answered by sanya2004srivastav
14

Answer:

Step-by-step explanation:

Sum of first n terms of AP, Sn = 2n2 + 5n Now choose n =1 and put in the above formula,First term = 2+5 = 7 Now put n=2 to get the sum of first two terms = 2x4 + 5x 2= 8 + 10 = 18 This means  first term + second term = 18 but first term =7 as calculated above so, second term = 18-7 = 11 So common difference becomes, 11-7 = 4 So the AP becomes, 7, 11, 15, ....nth term = a + (n - 1)d = 7 + (n-1)4 = 7 + 4n - 4 = 3 + 4n

Answered by onlygamelover11
4

Answer:

Step-by-step explanation:

Sum of first n terms of AP, Sn = 2n2 + 5n Now choose n =1 and put in the above formula,First term = 2+5 = 7 Now put n=2 to get the sum of first two terms = 2x4 + 5x 2= 8 + 10 = 18 This means  first term + second term = 18 but first term =7 as calculated above so, second term = 18-7 = 11 So common difference becomes, 11-7 = 4 So the AP becomes, 7, 11, 15, ....nth term = a + (n - 1)d = 7 + (n-1)4 = 7 + 4n - 4 = 3 + 4n

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