Talk:Microeconomics/The Effects of Taxation
"A marginal tax on the sellers of a good will shift the supply curve to the left until the vertical distance between the two supply curves is equal to the per unit tax; when other things remain equal, this will increase the price paid by the consumers (which is equal to the new market price),"
The vertical distance between the old supply curve and the new supply curve would equal the per unit tax only if the demand curve is perfectly elastic. Since this is not generally the case, then per unit tax is better explained as the vertical distance between the price consumers pay and the price firms receive from a transaction.
Additionally, does the supply curve shift to the left as the result of a sales tax? I think that the effect of a sales tax changes the quantity suppliers are willing to provide, making it a change in the quantity supplied along the supply curve, not a shift of the supply curve.