∫(1/sinx) dx
= ∫cscx dx
= ∫ [ 1/(cscx - cotx) ]d(cscx - cotx)
=ln|cscx - cotx| + C
∫(1/cosx) dx
= ∫secx dx
= ∫ [ 1/(seccx + tanx) ]d(seccx + tanx)
=ln|seccx + tanx| + C