Statement II is a standard property of definite integrals.
For statement I : I=∫π/6π/31+tanxdx=∫π/6π/31+cotxdx
I=∫π/6π/31+tanxtanxdx=∫π/6π/3cosx+sinxsinxdx=∫π/6π/3cosx+sinxcosxdx
2I=∫π/6π/3dx
2I=3π−6π
I=12π
Hence, statement I is false.