1. The problem statement, all variables and given/known data x''+b*x'+k*x=k*y+b*y' y=cos(omega*t) k is fixed, b - damping constant slowly increases. How does increasing the damping constant b affect the resonance peak? 2. The attempt at a solution Well, I thought the answers: It significantly decreases the height of the resonant peak. and It significantly decreases the frequency at which resonance happens. are correct. I have found a useful resource - http://physicsnet.co.uk/a-level-physics-as-a2/further-mechanics/forced-vibrations-resonance/ But these answers were marked as wrong. I have no idea why. What have I missed? Is it possible that this option is correct: It does not significantly change the shape nor the location of the resonance peak.?