(Px – 20) (100 – 2 Px + Pyg)

Differentiating with respect to P we get

100 – 4Px + Pyg + 40 = 0

I don't understand how this is calc... whenever I multiply through and take the deriv I get another answer. Do you first multiply Px through then 20??

2 answers

Pyg will be treated as a constant.

It doesn'matter how you multiply it out.

Px*100-2Px^2+PxPyg-2000+40Px+20Pyg=f

100-4Px+Pyg+40=0
How do the 2000 and 20pyg cancel out...the first pyg is still there?