Question

y=Asin2π(t/T - x/λ) or y=Asin2π(x/λ - t/T) ?
Help please

Answer 1

you usually see sin(kx - wt) where k = wavenumber = \({2\pi \over \lambda}\) and \(\omega = 2\pi f\)

you could figure it from there....

Answer 2

It does not matter as both formulae represent a wave travelling in the positive x direction.