Ask Singapore Homework?
Upload a photo of a Singapore homework and someone will email you the solution for free.
Question
junior college 1 | H2 Maths
One Answer Below
Anyone can contribute an answer, even non-tutors.
how do i find the hence part ?
Date Posted: 4 years ago
Views: 669
See 1 Answer
done
{{ upvoteCount }} Upvotes
clear
{{ downvoteCount * -1 }} Downvotes
Not 100% sure about this as I do not usually answer JC level questions.
Date Posted:
4 years ago
Answer and approach are correct.
But it would be clearer to show how the 2² is factored out for the second sum.
i.e along the lines of
-2 (2² + 4² + 6² + ... + (2n)² )
= -2 ( (1x2)² + (2x2)² + (3x2)² + ... + (2 x n)² )
= -2 (2²(1²) + 2²(2²) + 2²(3²) + ... + 2²n² )
= -2 (2²) (1² + 2² + 3² + ... + n²)
= -8 ∑(r = 1, to n terms) r²
But it would be clearer to show how the 2² is factored out for the second sum.
i.e along the lines of
-2 (2² + 4² + 6² + ... + (2n)² )
= -2 ( (1x2)² + (2x2)² + (3x2)² + ... + (2 x n)² )
= -2 (2²(1²) + 2²(2²) + 2²(3²) + ... + 2²n² )
= -2 (2²) (1² + 2² + 3² + ... + n²)
= -8 ∑(r = 1, to n terms) r²
360 Tutoring Program