如何求带绝对值的单边极限是这样的:limx=>-7^- (x+5)*[|x+7|/(x+7)]limx=>-7^+ (x+5)*[|x+7|/(x+7)]

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如何求带绝对值的单边极限
是这样的:
limx=>-7^- (x+5)*[|x+7|/(x+7)]
limx=>-7^+ (x+5)*[|x+7|/(x+7)]

lim(x→-7-0)(x+5)*[|x+7|/(x+7)]
= lim(x→-7-0)(x+5)*[(-1)(x+7)|/(x+7)]
= (-1)lim(x→-7-0)(x+5)
= (-1)(-7+5)
= 2,
lim(x→-7+0)(x+5)*[|x+7|/(x+7)]
= lim(x→-7-0)(x+5)*[(x+7)|/(x+7)]
= lim(x→-7-0)(x+5)
= (-7+5)
= -2.

带入2013年9月23日4时30分4秒