If the opportunity cost is constant, the PPF is a straight line; when the opp. cost of a good rises when it is produced more, then concave.
because it has increasing opportunity costs
correct.
Horizontal
I have never heard that the demand curve must be concave. In fact, it is most often modeled as either linear or convex. Common convex specifications include log-linear and constant-elasticity demand functions. A number of empirical papers attempt to estimate the shape of the demand curve for specific products but I am not familiar with anyone concluding that demand is concave generally.
A mirror that is curved outward is convex. A mirror that is curved inward is concave.
inword
no because its not curved
No, a concave polygon cannot be a regular polygon.
concave
bent or curved inwards
Curved mirrors are mirrors that have a spherical side. example - concave and convex.
a shape of a lens is curved outwards and concave one are curved in wards
The definition of concave is a curved like a segment of the interior of a circle or hollow sphere.
Inner curved surface is known as concave mirror because inner side of the spherical mirror is polished to reflect the light is called concave mirror,and concave mirror is know because concave mirror converges parallel beam of light.
Conclave or concave?
Definitions found on www.dictionary.com Concave: a curved like a segment of the interior of a circle or hollow sphere; hollow and curved Convex:having a surface that is curved or rounded outwardsBoth concave and convex mirrors are spherical mirrorsconcave mirrora spherical mirror whose reflecting surface is curved inwards is called a concave mirrorconvex mirrora spherical mirror whose reflecting surface is curved outwards is called a convex mirror