Sum of termsMediumQuestion 210007
Question
The sum 1 + 3 + 5 + ... + (2n−1) equals:
- An(n+1)/2
- Bn²Correct
- Cn(n−1)/2
- D2n(n−1)
Correct answer
n²
Explanation
Sum of first n odd numbers = n². The AP has a = 1, d = 2, n terms: Sₙ = (n/2)(2 + (n−1)2) = n².