∫(dx)/sinx
=∫(dx)/[2sin(x/2)cos(x/2)]
=∫[d(x/2)]/[tan(x/2)cos²(x/2)]
=∫[dtan(x/2)]/tan(x/2)
=ln│tan(x/2)│+C
另一种方法是
∫cscx dx=ln│cscx-cotx│+C