数学cos与sin角度为什么用2π是什么意思?
1个回答
函数应该是R的子集到R的子集的映射,
角度不是一个数的概念,而是一个符号,用角度不符合函数的定义,因此自变量应该用弧度来表示,否则就不是函数了;
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