limit as x approaches infinity of (x^2+2x+5)/(e^{3x)}

解答

x \to \infty lim (\frac{x ^{2} + 2 x + 5}{e ^{3 x}})

0

求解步骤

x \to \infty lim (\frac{x ^{2} + 2 x + 5}{e ^{3 x}})

乘开

\frac{x ^{2} + 2 x + 5}{e ^{3 x}} : \frac{x ^{2}}{e ^{3 x}} + \frac{2 x}{e ^{3 x}} + \frac{5}{e ^{3 x}}

= x \to \infty lim (\frac{x ^{2}}{e ^{3 x}} + \frac{2 x}{e ^{3 x}} + \frac{5}{e ^{3 x}})

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

不定型除外

= x \to \infty lim (\frac{x ^{2}}{e ^{3 x}}) + x \to \infty lim (\frac{2 x}{e ^{3 x}}) + x \to \infty lim (\frac{5}{e ^{3 x}})

x \to \infty lim (\frac{x ^{2}}{e ^{3 x}}) = 0

x \to \infty lim (\frac{2 x}{e ^{3 x}}) = 0

x \to \infty lim (\frac{5}{e ^{3 x}}) = 0

= 0 + 0 + 0

化简

= 0

\frac{d}{d x} (e^{x} cos (x) + e^{x} sin (x))

\int \frac{sin ^{2} ( 3 x )}{cos ( 3 x )} d x

\int \frac{1}{( 169 - x ^{2} ) ^{\frac{3}{2}}} d x

t a y l or 1 - x^{3}

a re a 6 x^{2}, x^{2} + 5