Answer:
<em>Choice D.</em>
Step-by-step explanation:
Vertical line test for functions:
If a vertical line drawn anywhere on the graph intersects the graph in more than one point, it is not a function.
If you draw a vertical line passing through any point between x = -4 and x = 4, the line will intersect two points on the circle. The relation fails the vertical line test. That shows that this relation is not a function.
Answer:
Demand is Elastic when Price > 200 ; Demand is inelastic when Price < 200
Step-by-step explanation:
p = 400 - 4x
4x = 400 - p
x = (400 - p) / 4 → x = 100 - p/4
Elasticity of demand [ P ed ] = (Δx / Δp) x (p / x)
Δx / Δp [Differentiating x w.r.t p] = 0 - 1/4 → = -1/4
P ed = <u>-1</u> x<u> p </u>
4 (400 - p)/4
= <u>-1</u> x <u> 4p </u> = -p / (400-p)
4 (400 - p)
Price Elasticity of demand : only magnitude is considered, negative sign is ignored (due to negative price demand relationship as per law of demand).
So, Ped = p / (400 - p)
Demand is Elastic when P.ed > 1
p / (400-p) > 1
p > 400 - p
p + p > 400 → 2p > 400
p > 400 / 2 → p > 200
Demand is inelastic when P.ed < 1
p / (400-p) < 1
p < 400 - p
p + p < 400 → 2p < 400
p < 400 / 2 → p < 200
It means "approximately" instead of "equal to"
