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 $$$\int_{0}^{\pi}\left( \frac{x \sin{\left(x \right)}}{2} \right)dx$$$
First, calculate the corresponding indefinite integral: $$$\int{\frac{x \sin{\left(x \right)}}{2} d x}=- \frac{x \cos{\left(x \right)}}{2} + \frac{\sin{\left(x \right)}}{2}$$$ (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.
$$$\left(- \frac{x \cos{\left(x \right)}}{2} + \frac{\sin{\left(x \right)}}{2}\right)|_{\left(x=\pi\right)}=\frac{\pi}{2}$$$
$$$\left(- \frac{x \cos{\left(x \right)}}{2} + \frac{\sin{\left(x \right)}}{2}\right)|_{\left(x=0\right)}=0$$$
$$$\int_{0}^{\pi}\left( \frac{x \sin{\left(x \right)}}{2} \right)dx=\left(- \frac{x \cos{\left(x \right)}}{2} + \frac{\sin{\left(x \right)}}{2}\right)|_{\left(x=\pi\right)}-\left(- \frac{x \cos{\left(x \right)}}{2} + \frac{\sin{\left(x \right)}}{2}\right)|_{\left(x=0\right)}=\frac{\pi}{2}$$$
Answer: $$$\int_{0}^{\pi}\left( \frac{x \sin{\left(x \right)}}{2} \right)dx=\frac{\pi}{2}\approx 1.5707963267949$$$