JEE Main 2026 Mathematics question
Let the sum of the first n terms of an A.P. be 3n²+5n. Then the sum of squares of the first 10 terms of the A.P. is:
Answer: (C)
Solution
aₙ = Sₙ−Sₙ₋₁ = 6n+2. Summing (6n+2)² for n=1 to 10 gives 15220.
Let the sum of the first n terms of an A.P. be 3n²+5n. Then the sum of squares of the first 10 terms of the A.P. is:
aₙ = Sₙ−Sₙ₋₁ = 6n+2. Summing (6n+2)² for n=1 to 10 gives 15220.