can help solve? not sure if it’s my morning brain or what but I can’t solve

Ask Singapore Homework?

Upload a photo of a Singapore homework and someone will email you the solution for free.

junior college 1 | H2 Maths
2 Answers Below

Anyone can contribute an answer, even non-tutors.

can help solve? not sure if it’s my morning brain or what but I can’t solve these 2...

Date Posted: 4 years ago

3 Upvotes

0 Downvotes

The key is to realise u_n is an arithmetic progression

4 years ago

First part actually no need to find un. Just take SN - S4

N(N+14)/3 - 4(4+14)/3

= (N² + 14N)/3 - 24

Since the sum formula already given

Matthew Fan

4 years ago

That is right, yes the solution can be made much shorter that way

Amy Ang

4 years ago

thanks!

0 Upvotes

0 Downvotes

And this is the second question. Time for some self-advertising: Im offering free trial of online lessons. If interested, approach me at 8533 3271