I'm not quite sure how to solve this problem. I tried one step but don't know what to do next. It seems weird.
dw/dt=-lambdaW(t) with W(0)=Winitial
All I did was separate:
dw/-lambdaW(t)=dt but don't now what to do from here because I don't know what W(t) is.
Can anyone help? I will deeply appreciate it! thank you!

