定積分與廣義積分計算器
逐步計算定積分與瑕積分
此計算器將嘗試計算定積分(即帶有上下限的積分),包含廣義積分,並顯示步驟。
Solution
Your input: calculate $$$\int_{0}^{3}\left( \frac{x \left(x - 9\right) \left(x - 6\right)}{9} \right)dx$$$
First, calculate the corresponding indefinite integral: $$$\int{\frac{x \left(x - 9\right) \left(x - 6\right)}{9} d x}=\frac{x^{2} \left(x^{2} - 20 x + 108\right)}{36}$$$ (for steps, see indefinite integral calculator)
According to the Fundamental Theorem of Calculus, $$$\int_a^b F(x) dx=f(b)-f(a)$$$, so just evaluate the integral at the endpoints, and that's the answer.
$$$\left(\frac{x^{2} \left(x^{2} - 20 x + 108\right)}{36}\right)|_{\left(x=3\right)}=\frac{57}{4}$$$
$$$\left(\frac{x^{2} \left(x^{2} - 20 x + 108\right)}{36}\right)|_{\left(x=0\right)}=0$$$
$$$\int_{0}^{3}\left( \frac{x \left(x - 9\right) \left(x - 6\right)}{9} \right)dx=\left(\frac{x^{2} \left(x^{2} - 20 x + 108\right)}{36}\right)|_{\left(x=3\right)}-\left(\frac{x^{2} \left(x^{2} - 20 x + 108\right)}{36}\right)|_{\left(x=0\right)}=\frac{57}{4}$$$
Answer: $$$\int_{0}^{3}\left( \frac{x \left(x - 9\right) \left(x - 6\right)}{9} \right)dx=\frac{57}{4}=14.25$$$