Tech A says that a closed loop system means the ECM is receiving feedback and adjusting the fuel injector on time as needed. Tech B says that lean means there is not enough air in the air fuel mixture. Who is right?

Does the distance travelled by an oscillating mass between times t=0 and t2 equal the displacement of the particle over the same time period if t2> t/2? hint: consider a sine wave starting at t1=0, then consider a closing wave starting at t1=0, for your explanation.