函数f(x)在点x=a处有定义是什么意思 函数F(x)在X。的极限为A 叙述定义
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有定义是说函数在这一点处有意义，也就是说当x=a是f（x）有唯一确定的值与之对应。就是指x=a在定义域内。让f(a)有意义
那个指数值可以带入函数
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绛旓細鍏蜂綋鍦拌锛屽鏋滀竴涓嚱鏁癴(x)鍦ㄧ偣x=a澶勮繛缁紝浠ヤ笅鏉′欢蹇呴』鍚屾椂婊¤冻锛1. 鍑芥暟鍦ㄧ偣x=a鐨勫畾涔夊煙涓湁瀹氫箟锛屽嵆f(a)瀛樺湪銆2. 璇ョ偣鐨勬瀬闄愬瓨鍦紝鍗砽im(xa) f(x)瀛樺湪銆3. 鍑芥暟鍦ㄧ偣x=a鐨勬瀬闄愬肩瓑浜庡嚱鏁板湪鐐箈=a鐨勫嚱鏁板硷紝鍗砽im(xa) f(x) = f(a)銆傛崲鍙ヨ瘽璇达紝褰撳嚱鏁板湪鏌愪竴鐐硅繛缁椂锛屾垜浠彲浠...
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绛旓細绛:f(x)鍦x=a澶鍙互鏈夋剰涔,涔熷彲浠ユ病鏈夋剰涔.浜嬪疄涓婂綋x鈫抋鏃,limf(x)=A涓鍑芥暟f(x)鍦╝澶勬湁娌鏈夊畾涔娌℃湁蹇呯劧鑱旂郴濡備緥瀛:lim(x-->2)(x^2-4)/(x-2)=4.姝ゆ椂f(x)=(x^2-4)/(x-2)鍦▁=2鐐瑰娌℃湁鎰忎箟,鏋侀檺瀛樺湪.lim(x-->2)(x+2)=4...
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