定積分・広義積分計算機
定積分と広義積分を手順を追って計算する
この計算機は、定積分(すなわち上下限のある積分)を、広義積分も含めて、解法手順を示しながら計算を試みます。
Solution
Your input: calculate $$$\int_{0}^{\frac{\pi}{4}}\left( \cot{\left(x + \frac{\pi}{4} \right)} \right)dx$$$
First, calculate the corresponding indefinite integral: $$$\int{\cot{\left(x + \frac{\pi}{4} \right)} d x}=\ln{\left(\left|{\sin{\left(x + \frac{\pi}{4} \right)}}\right| \right)}$$$ (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.
$$$\left(\ln{\left(\left|{\sin{\left(x + \frac{\pi}{4} \right)}}\right| \right)}\right)|_{\left(x=\frac{\pi}{4}\right)}=0$$$
$$$\left(\ln{\left(\left|{\sin{\left(x + \frac{\pi}{4} \right)}}\right| \right)}\right)|_{\left(x=0\right)}=\ln{\left(\frac{\sqrt{2}}{2} \right)}$$$
$$$\int_{0}^{\frac{\pi}{4}}\left( \cot{\left(x + \frac{\pi}{4} \right)} \right)dx=\left(\ln{\left(\left|{\sin{\left(x + \frac{\pi}{4} \right)}}\right| \right)}\right)|_{\left(x=\frac{\pi}{4}\right)}-\left(\ln{\left(\left|{\sin{\left(x + \frac{\pi}{4} \right)}}\right| \right)}\right)|_{\left(x=0\right)}=- \ln{\left(\frac{\sqrt{2}}{2} \right)}$$$
Answer: $$$\int_{0}^{\frac{\pi}{4}}\left( \cot{\left(x + \frac{\pi}{4} \right)} \right)dx=- \ln{\left(\frac{\sqrt{2}}{2} \right)}\approx 0.346573590279973$$$