📝 题目
例 6 求 $\displaystyle{\int \tan x\mathrm{\;d}x,\int \cot x\mathrm{\;d}x}$ .
💡 答案与解析
解 $\displaystyle \int \tan x\mathrm{\;d}x = - \int \frac{\mathrm{d}\left( {\cos x}\right) }{\cos x} = - \ln \left| {\cos x}\right| + C$ .
$$ \int \cot x\mathrm{\;d}x = \int \frac{\mathrm{d}\left( {\sin x}\right) }{\sin x} = \ln \left| {\sin x}\right| + C. $$