limit as x approaches infinity of xy

解答

x \to \infty lim (x y)

\infty

求解步骤

x \to \infty lim (x y)

x \to a lim [c \cdot f (x)] = c \cdot x \to a lim f (x)

= y \cdot x \to \infty lim (x)

运用一般极限法则:

x \to \infty lim (x) = \infty

= y \cdot \infty

化简

y \cdot \infty : \infty

= \infty

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