定义域 (x^3+4x^2)/(7x^2-2)

解答

定义域

\frac{x ^{3} + 4 x ^{2}}{7 x ^{2} - 2}

x < - \frac{2}{7} or - \frac{2}{7} < x < \frac{2}{7} or x > \frac{2}{7}

间隔符号

(- \infty, - \frac{2}{7}) \cup (- \frac{2}{7}, \frac{2}{7}) \cup (\frac{2}{7}, \infty)

求解步骤

找到无定义的点（奇点）:

x = \frac{2}{7}, x = - \frac{2}{7}

函数定义域

x < - \frac{2}{7} or - \frac{2}{7} < x < \frac{2}{7} or x > \frac{2}{7}

p a r i t y f (x) = sin (- π t)

a sy m pt o t es f (x) = \frac{5}{x ^{2} + 2 x - 3}

in t erce pt s \frac{( x + 1 ) ( x - 3 )}{x - 3}

in t erce pt s f (x) = x^{2} - 16

d o main 7 - x^{2}