limit as x approaches 9-of (|x-9|)/(x-9)

解答

x \to 9 - lim (\frac{∣ x - 9 ∣}{x - 9})

- 1

求解步骤

x \to 9 - lim (\frac{∣ x - 9 ∣}{x - 9})

当

x \to 9 -

时,

x - 9

为负. 因此

∣ x - 9 ∣ = - x + 9

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

\frac{- x + 9}{x - 9} = - 1

= x \to 9 - lim (- 1)

x \to a lim c = c

= - 1

\frac{d}{d x} (3 2 x)

\int \frac{sec ^{3} ( x )}{tan ^{2} ( x )} d x

\frac{\partial}{\partial x} (16 x + 32 y - 1600)

d er i v a t i v e \frac{x}{x + 1}

n = 0 \sum \infty \frac{1}{n ^{3} - n}