Elasticity of Demand

At what level is demand perfectly elastic/inelastic?

when the demand curve is horizontal/ vertical

Right but what does POD demand equal (numerical range) for you to say it’s perfectly elastic/inelastic?

perfectly elastic ==> elasticity = infinity because deltaQ/deltaP = q/0=infinity. perfectly inelastic ==> delatQ/deltaP = 0/P = 0

Perfect, thanks… Thought it was something like that but just wasn’t sure.