demand shifts - will only change price  

• quantity produced by monopoly still stays the same
• intersection of MR=MC stays the same

tax effect - increases price by less than tax in a competitive market  

• in monopoly, price can sometimes rise higher than the tax
• MC' = MC + tax
  • basically, the marginal cost shifts up by a constant

• demand
• marginal revenue
• marginal cost
• marginal cost plus tax
• p = price before tax
• p* = price after tax, increased by more than the tax

deadweight loss - occurs along w/ consumer surplus loss w/ change to monopoly  

• normally in competitive market, price found at intersection of marginal cost and market demand
  • price set higher than this in monopoly >> loss of consumer surplus
  • less quantity produced >> deadweight loss
• price regulation can get rid of deadweight loss in a monopoly
  • sets price minimum in competitive market, sets price maximum in a monopoly market

natural monopoly - has a much more efficient production than other firms  

• makes it unprofitable for other firms to even continue production
• possible w/ large economies of scale