Trig lesson out of order?

Graphs of Trig Functions > Finding amplitude and midline of sinusoidal functions from their formulas 

The video for this lesson could be improved.  It approaches, but doesn't quite cover: f(x)=asin(bx+c)+d.  Then the practice questions are written as if it DID cover it completely.  Perhaps the video should open with that equation and do a full breakdown of the variables and transformations.