Distinguish between the meaning of the expressions "change in demand" and "change in the quantity demanded"

Question

answer should base on micro economics

Answer 1

A change in demand indicates that a change in the entire demand curve has caused the curve to shift to a different level. For example, say butter has just been proven to cause brain erosion (assume this is a bad thing). Then, the demand for butter will decrease, since people will want less of it at the current price and all other prices.

A change in quantity demanded does not involve shifting the demand curve. Instead, it is a movement along the demand curve to a different price and quantity. But it continues to be the same demand curve. This could result from a change in supply that will change the equilibrium points.

Hope this helps.

Answer 2

Meaning Distinguish