limit as x approaches 3+of (x+9)/(x-3)

解

x \to 3 + lim (\frac{x + 9}{x - 3})

\infty

解答ステップ

x \to 3 + lim (\frac{x + 9}{x - 3})

\frac{x + 9}{x - 3} = (x + 9) \frac{1}{x - 3}

= x \to 3 + lim ((x + 9) \frac{1}{x - 3})

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

不定形式の場合を除く

= x \to 3 + lim (x + 9) \cdot x \to 3 + lim (\frac{1}{x - 3})

x \to 3 + lim (x + 9) = 12

x \to 3 + lim (\frac{1}{x - 3}) = \infty

= 12 \cdot \infty

無限大の特性を適用する:

c \cdot \infty = \infty

= \infty