limit as x approaches-1 of 7x-2x^2

解答

x \to - 1 lim (7 x - 2 x^{2})

- 9

求解步骤

x \to - 1 lim (7 x - 2 x^{2})

代入值

x = - 1

= 7 (- 1) - 2 (- 1)^{2}

化简

7 (- 1) - 2 (- 1)^{2} : - 9

= - 9

d er i v a t i v e y = 1 + 2 x

y^{^{''}} + 12 y^{^{'}} + 117 y = 0

\frac{\partial}{\partial x} (2 x - \frac{3}{x ^{2}} + y)

d er i v a t i v e y = 2 - x

y^{^{''}} - y^{^{'}} + 5 y = 3