limit as x approaches 0 of (4x-2x^2)/(sin(x))

解答

x \to 0 lim (\frac{4 x - 2 x ^{2}}{sin ( x )})

4

求解步骤

x \to 0 lim (\frac{4 x - 2 x ^{2}}{sin ( x )})

乘开

\frac{4 x - 2 x ^{2}}{sin ( x )} : \frac{4 x}{sin ( x )} - \frac{2 x ^{2}}{sin ( x )}

= x \to 0 lim (\frac{4 x}{sin ( x )} - \frac{2 x ^{2}}{sin ( 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 0 lim (\frac{4 x}{sin ( x )}) - x \to 0 lim (\frac{2 x ^{2}}{sin ( x )})

x \to 0 lim (\frac{4 x}{sin ( x )}) = 4

x \to 0 lim (\frac{2 x ^{2}}{sin ( x )}) = 0

= 4 - 0

化简

= 4

x \to - 2 lim (\frac{2 x + 1}{x - 3})

x \to + 0 + lim (sin (x) n x)

n \to 1 lim (\frac{n ^{3} - 1}{n - 1})

x \to 0 lim (\frac{x ^{2} - 2 x}{3 x})

x \to - 8 - lim (f (x))