函数在区间有意义是什么意思?指的是x在该区间还是y在该区间? 已知函数y=√(ax+1)在区间xxx上有意义 问，这里的有...
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\u5982 y = 1/x \u5728\uff081\uff0c+\u221e\uff09\u6709\u5b9a\u4e49\uff0c
\u4f46 y = sinx / x \u5728\uff08-1\uff0c1\uff09\u4e0a\u7684 x = 0 \u5904\u5c31\u65e0\u5b9a\u4e49\uff08\u867d\u7136\u5728\u533a\u95f4\u7684\u5176\u5b83\u5904\u4e5f\u90fd\u6709\u503c\uff09\u3002
\u201c\u521d\u7b49\u51fd\u6570\u5728\u5176\u5b9a\u4e49\u533a\u95f4\u5185\u53ef\u5bfc\u201d\u8fd9\u53e5\u8bdd\u662f\u9519\u7684\u3002y=|x|=\u221a(x^2),\u8fd9\u662f\u4e00\u4e2a\u521d\u7b49\u51fd\u6570\uff0c\u5b9a\u4e49\u533a\u95f4\u4e3a\uff08-\u221e\uff0c+\u221e\uff09\uff0c\u4f46\u5728x=0\u5904\u662f\u4e0d\u53ef\u5bfc\u7684\u3002
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\u6ce8\u610f\uff1a
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函数在区间有意义等价于函数在区间有定义，换言之，在这个区间的每一点都有函数值
指的是x在该区间
意思就是说在该区间是函数定义域的子集，也就是说X在该区间可以取到值。
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