We have seen the number 1,618 (1,61803398 to be more accurate), in three different situations ● the ratio of the terms of the Fibonacci sequence
● continued square roots
● continued fractions.

This number is called ‘phi’ or . It is an important number and is also called the Golden ratio. has many special properties. Let

1. Write down the value of (1)
2. What do you notice? (2)
3. Use the fact that to solve for and show that .