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21 小時前 · As of the 2021 census, the population of Russia was 147.2 million.[9] It is the most populous country in Europe, and the ninth-most populous country in the world, with a population density of 8.5 inhabitants per square kilometre (22 inhabitants/sq mi).[10] As of 2020, the overall life expectancy in Russia at birth was 71.54 years (66.49 years ...
3 天前 · Amyotrophic lateral sclerosis (ALS), also known as motor neurone disease (MND) or Lou Gehrig's disease in the United States, is a rare but terminal neurodegenerative disorder that results in the progressive loss of both upper and lower motor neurons that normally control voluntary muscle contraction.[3] ALS is the most common form of the motor ...
5 天前 · What links here Related changes Upload file Special pages Permanent link Page information Cite this page Get shortened URL Download QR code In mathematics, sine and cosine are trigonometric functions of an angle.The sine and cosine of an acute angle are defined in the context of a right triangle: for the specified angle, its sine is the ratio of the length of the side that is opposite that ...
1 天前 · Brazil,[b] officially the Federative Republic of Brazil,[c] is the largest and easternmost country in South America and in Latin America. Brazil is the world's fifth-largest country by area and the seventh most populous. Its capital is Brasília, and its most populous city is São Paulo. The federation is composed of the union of the 26 states ...
1 天前 · Location of Panama between the Pacific Ocean (bottom) and the Caribbean Sea (top), with the canal at top center. The Panama Canal (Spanish: Canal de Panamá) is an artificial 82-kilometre (51-mile) waterway in Panama that connects the Atlantic Ocean with the Pacific Ocean, cutting across the Isthmus of Panama, and is a conduit for maritime trade.
1 天前 · Titanium is a chemical element; it has symbol Ti and atomic number 22. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion in sea water, aqua regia, and chlorine. Titanium was discovered in Cornwall, Great Britain, by William ...
3 天前 · A plot of normal distribution (or bell-shaped curve) where each band has a width of 1 standard deviation – See also: 68–95–99.7 rule. Cumulative probability of a normal distribution with expected value 0 and standard deviation 1 In statistics, the standard deviation is a measure of the amount of variation of a random variable expected about its mean.
