1. The problem statement, all variables and given/known data what is the energy loss of the damped oscillator. 2. Relevant equations x(t) = A*e^(-Bt)*cos(w1*t) T = 1/2 mv^2 3. The attempt at a solution To solve for an undamped oscillator, I took the derivative of the equation of motion x(t) and plugged the amplitude into 1/2 mv^2 equation and that worked. Now a damping effect has been added. I want to do the same thing. Take the derivative of the equation above and plug its amplitude into the kinetic energy formula. Subtract to get the energy loss. I did this and I received my answer, but I can't tell if it is reasonable. if my mass is on a spring and I pull it back and let it go, its max velocity will be at pi/2. so when I take my derivative and I get a dx/dt = sine + cosine both multiplied by constants. the cosine term will be zero and the sine term will be 1*maxvelocity. which I can plug into my kinetic energy formula. and then subtract to get the energy loss Is this a reasonable approach? I couldn't find anything about this, so I am nervous.