The definition of the golden section is: if a line segment is divided into two parts, so that the ratio of the whole line segment to the longer part is equal to the ratio of the longer part to the shorter part, then this ratio is the golden section ratio, that is, (A+B)/A=A/B=φ. The detailed explanation is as follows:

1, the golden section is a mathematical proportion, usually expressed by the Greek letter φ(phi). This ratio is considered to be the most harmonious and beautiful. The golden ratio is about 1.6 180339887 ... This is an irrational number, that is, it cannot be expressed by the ratio of two integers. This ratio is considered to be the most beautiful because it gives people a sense of harmony and balance visually.

2. The golden section is widely used in art and design. For example, the Parthenon in ancient Greece and Leonardo da Vinci's The Last Supper all used the golden section principle. In photography and movies, the golden section is also used for composition to create attractive pictures.

3. The golden section is also widely used in nature. For example, the arrangement of leaves, flowers and seeds of many plants follows the golden ratio. In addition, some parts of the human body, such as facial features and body proportions, are also close to the golden ratio.

Knowledge about gold

1. Gold is a rare yellow precious metal with the chemical symbol of Au. It is one of the rarest elements on the earth, accounting for about five millionths of the total mass of the earth's crust. Gold has good ductility, electrical conductivity and corrosion resistance, so it is widely used to make jewelry, coins, investment products and so on.

2. The history of gold can be traced back to 4000 BC, and the ancient Egyptians first began to mine and use gold. In ancient times, gold was regarded as a symbol of power and wealth, and it was also an important element in many myths and legends of civilization.

3. The price of gold is influenced by many factors, including supply and demand, inflation, monetary policy and geopolitical risks. Because of its characteristics of maintaining and increasing value, gold is usually regarded as a "safe haven" asset during the period of economic instability or inflation.

4. There are various ways to invest in gold, including physical gold, gold ETF, gold futures and gold stocks. Among them, physical gold is the most traditional investment method, and investors can buy gold bars and coins directly. Gold ETF is a way to invest by buying exchange-traded funds backed by gold, which has the advantages of good liquidity and low transaction cost.