The figure shows a taut string, initially aligned with the x-axis, which carries a waveform travelling towards the right without any change its shape. The bold line and the dotted line indicate the displacement of the string (i.e., shape of the wave form)at time = t second at time = (t + dt) second, respectively. The speed of particle at point P at t = 2 sec is 1cm/s. Choose the correct statement (s) from the following (assume that dt is positive & slope of y-x at p is $45°$ )