Prove of Integration Formulae

Please prove the following expression completely

1. ∫ (1/x) dx = ln x + c
2. ∫ (e^x) dx = e^x + c
3. ∫ (a^x) dx = a^x ln a + c
4. ∫ tanx dx = ln |sec x| + c
5. ∫ cotx dx = ln |sin x| + c