Introduction
to Economics ECO401
VU
Lesson
3.2
ELASTICITIES
(CONTINUED.............)
Elastic
and Inelastic
Demand:
Slope
and elasticity of demand
have an inverse relationship.
When slope is high
elasticity of
demand
is low and vice
versa.
When
the slope of a demand curve
is infinity, elasticity is zero
(perfectly inelastic
demand);
and
when the slope of a demand
curve is zero, elasticity is
infinite (perfectly elastic
demand).
Unit
elasticity means that a 1%
change in price will result
in an exact 1% change in
quantity
demanded.
Thus elasticity will be
equal to one. A unit elastic
demand curve plots as
a
rectangular
hyperbola. Note that a
straight line demand curve
cannot have unit elasticity
as the
value
of elasticity changes along
the straight line demand
curve.
Total
revenue and
Elasticity:
Total
revenue (TR) = Price x
Quantity; when the demand
curve is inelastic, TR increases
as
the
price goes up, and
vice versa; when the
demand curve is elastic, TR
falls as the price
goes
up,
and vice versa.
Determinants
of price elasticity of
demand:
1.
Number of close substitutes
within the market - The
more (and closer)
substitutes
available
in the market the more
elastic demand will be in
response to a change in price.
In
this
case, the substitution
effect will be quite
strong.
2.
Percentage of income spent on a
good - It may be
the case that the
smaller the
proportion
of income spent taken up
with purchasing the good or
service the more
inelastic
demand
will be.
3.
Time period under
consideration - Demand
tends to be more elastic in
the long run
rather
than
in the short run. For
example, after the two
world oil price shocks of
the 1970s - the
"response"
to higher oil prices was
modest in the immediate
period after price
increases, but
as
time passed, people found
ways to consume less
petroleum and other oil
products. This
included
measures to get better
mileage from their cars;
higher spending on insulation
in
homes
and car pooling for
commuters. The demand for
oil became more elastic in
the long-
run.
Effects
of Advertising on Demand
Curve:
Advertising
aims to:
·
Change
the slope of the demand
curve make it more
inelastic. This is done
by
generating
brand loyalty;
·
Shift
the demand curve to the
right by tempting the
people's want for that
specific
product.
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