Question:
Question 1: If the sum of n terms of an A.P. be 3n2 n and its common difference is 6 , then its first term is
Answer:
Let a is the first term and d is the common difference of AP
Given d = 6
Now sum of n terms of AP = 3n2 + n
=> (n/2){2a + (n-1)d} = 3n2 + n
=> (1/2){2a + (n-1)d} = 3n + 1
=> (1/2){2a + (n-1)6} = 3n + 1
=> a + (n-1)3 = 3n + 1
=> a + 3n - 3 = 3n + 1
=> a - 3 = 1
=> a = 3+1
=> a = 4
So the first term of AP is 4.
Not what you are looking for? Go ahead and submit the question, we will get back to you.
