A wave packet with center frequency ω is propagating in dispersive medium with phase velocity of 1.5 x 10^3 m/s. When the frequency ω is increased by 2%, the phase velocity is found to decrease by 3%. What is the group velocity of the wave packet?
My answer would be that the group velocity should be half the phase velocity but that does not seem to be the correct answer , where am i going wrong ? could you guide me to more sources of similar problems (other than wikipedia, MIT ocw etc. ) ?