A book with many error contains four different formulas for the displacement y of a parties undergoing a certain periodic motion : (a) y = a sin 2π t/T (b) y = a sin vt (c) y = (a/T) sin t/a (d) y = (a √2 (sin 2π t/T + cos 2π t/T) (a = maximum displacement of the particle, v = speed of the particle, T = time-period of motion), Rule out the wrong formulas on dimensional grounds.