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3 天前 · Gold is a chemical element with the symbol Au (from the Latin word aurum) and the atomic number 79. In its pure form, it is a bright, slightly orange-yellow, dense, soft, malleable, and ductile metal. Chemically, gold is a transition metal, a group 11 element, and one of the noble metals. It is one of the least reactive chemical elements ...
3 天前 · Golden ratio. A golden rectangle with long side a + b and short side a can be divided into two pieces: a similar golden rectangle (shaded red, right) with long side a and short side b and a square (shaded blue, left) with sides of length a. This illustrates the relationship a + b a = a b = φ.
6 天前 · In trigonometry, trigonometric identities are equalities that involve trigonometric functions and are true for every value of the occurring variables for which both sides of the equality are defined. Geometrically, these are identities involving certain functions of one or more angles.
3 天前 · In physical cosmology, cosmic inflation, cosmological inflation, or just inflation, is a theory of exponential expansion of space in the early universe. The inflationary epoch is believed to have lasted from 10 −36 seconds to between 10 −33 and 10 −32 seconds after the Big Bang.
3 天前 · t. e. The viscosity of a fluid is a measure of its resistance to deformation at a given rate. [1] For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water. [2] Viscosity is defined scientifically as a force multiplied by a time divided by an area.
1 天前 · It is the world's second largest economy by nominal GDP, behind the United States, and the world's largest economy since 2016 when measured by purchasing power parity (PPP). [note 2] China accounted for 19% of the global economy in 2022 in PPP terms, [34] and around 18% in nominal terms in 2022.
19 小時前 · Gross domestic product (GDP) is the market value of all final goods and services from a nation in a given year. [2] . Countries are sorted by nominal GDP estimates from financial and statistical institutions, which are calculated at market or government official exchange rates.
