∫ dx/sinx
=∫ dx/(2*sin(x/2)*cos(x/2))
=∫ d(x/2)/(sin(x/2)*cos(x/2))
=∫ (d(x/2)/cos^2(x/2)) / (sin(x/2)/cos(x/2))
=∫ d(tan(x/2)) / tan(x/2)
=ln | tan(x/2) | +C
有不懂欢迎追问
∫ dx/sinx
=∫ dx/(2*sin(x/2)*cos(x/2))
=∫ d(x/2)/(sin(x/2)*cos(x/2))
=∫ (d(x/2)/cos^2(x/2)) / (sin(x/2)/cos(x/2))
=∫ d(tan(x/2)) / tan(x/2)
=ln | tan(x/2) | +C
有不懂欢迎追问