If \(\rm a_n=\displaystyle \int_0^{\pi / 2} \frac{\sin ^2 n x}{\sin x} d x \), then a₂ – a₁, a₃ – a₂, a₄ – a₃, .... are in

none of these

If \(\rm a_n=\displaystyle \int_0^{\pi / 2} \frac{\sin ^2 n x}{\sin x} d x \), then a2 – a1, a3 – a2, a4 – a3, .... are in