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
2 Answers Below

Anyone can contribute an answer, even non-tutors.

Answer This Question
Sally Tan
Sally Tan

junior college 1 chevron_right H2 Maths chevron_right Singapore

Hello! Please help me with this question :)

Date Posted: 3 years ago
Views: 332

See 2 Answers

done {{ upvoteCount }} Upvotes
clear {{ downvoteCount * -1 }} Downvotes
Eric Nicholas K
Eric Nicholas K's answer
5997 answers (Tutor Details)
1st
Q5a
done {{ upvoteCount }} Upvotes
clear {{ downvoteCount * -1 }} Downvotes
Eric Nicholas K
Eric Nicholas K's answer
5997 answers (Tutor Details)
Second one, but not so sure about this one
J
J
3 years ago
Fun fact :

The common ratio (√5 - 1)/2 is actually the reciprocal of the golden ratio φ ,(1 + √5)/2
Eric Nicholas K
Eric Nicholas K
3 years ago
Actually, I was thinking that the final value of the expression I answered was the golden ratio itself. Seems like I got the values mixed up.
J
J
3 years ago
The conjugate, (-1 - √5)/2 is the negative of the golden ratio
J
J
3 years ago
Another fun fact :

(y/x)² + (y/x) - 1 = 0
(y/x)² = 1 - (y/x) ①

The 1st term of the G.P = x²

2nd term = x² (y/x)

3rd term = x² (y/x)²
= x² (1 - y/x)
= x² - x² (y/x) (from ①)
= 1st term - 2nd term

4th term
= x² (y/x)³
= x² (y/x)² (y/x)
= (x² - x² (y/x)) (y/x)
= x²(y/x) - x²(y/x)²
= 2nd term - 3rd term


Likewise,
5th term = 3rd term - 4th term
6th term = 4th term - 5th term
...
...
nth term = (n-2)th term - (n-1)th term


This can be rewritten as :

nth term + (n-1)th term = (n-2)th term

This G.P is actually a generalised Fibonacci sequence, but in reverse order.