sec 与csc的原函数

∫secxdx =∫secx(secx+tanx)dx/(secx+tanx) =∫(sec²x+tanxsecx)dx/(secx+tanx) =∫d(tanx+secx)/(secx+tanx) =ln|secx+tanx|+C

原题应是: ∫cscxdx=? ∫cscxdx=∫(1/sinx)dx =∫(1/(2sin(x/2)cos(x/2)))dx =∫(1/(tan(x/2))dtan(x/2) =ln|tan(x/2)|+C