Often it is more desirable to have a roll-off versus frequency of the rejection in the stopband; for example resampling filters where all the alias image locations fold into the first Nyquist Zone. What is a VERY simple change you can make to the coefficient solution provided by the Parks-McClellan algorithm that will convert the "equiripple" stopband to one that rolls off with greater rejection (at the expense of exceeding target limits near the transition, and increasing passband ripple)? Note: This is a great "trick" that I learned from fred harris.
Note- for full credit please explain why this "trick" works.
To help illustrate the end result, see the plot below showing a standard design using P-McC before and after the simple modification. Here we see the stop band rejection with a roll-off instead of being flat, but increased passband ripple and degraded rejection immediately near the beginning of the stopband, but overall significantly better rejection.
Before (blue) and after (red) modifcation to filter coeff. Note the region close to the transition where the stop band is worst, but overall rejection is much better:
Zoom in showing trade-off of degraded ripple in passband.