this is for a lab, but i wrote down the wrong equation. the lab was about attaching a 200 gram mass to a spring. we had to displace it so many cm, and than release it. we had to measure the period of the oscillations. but we are supposed to compare this measured period with a period obtained from the solution of the appropriate differential equation. i wrote down this for the diff eq, but im not sure if its right -kx -b(dx/dt)^2=m(d^2x/dt^2) is this the correct one? and if it is, where can i find the solution to this?