I remember having to teach this in the bad old days when we HAD to do
multiple choice.
To calculate point elasticity of supply select a given point on the supply
curve.
Project down to the x axis. Extend the SS curve to the x axis.
Then measure from the origin to the quantity supplied (right hand)
Measure from where the supply curve intersect the x axis to quantity
supplied (left hand)
Point PES = right hand / left hand - cos the mathematicians tell us so
That means any linear SS line that first hits the y axis is elastic. SS
curves that first hit the x axis are inelastic
Any linear SS line passing through the origin has unitary elasticity.
Having to teach KIDS THAT WAS EXACTLY WHY I LOATHED M/C.
AND AS YOU CAN SEE THE PAIN IS STILL WITH ME BECAUSE SOME 15 YEARS LATER I
CAN STILL REMEMBER HOW TO DO THAT.... SAD OR WHAT :-)
Ps Those colleagues who LIKE m/c please not I am exaggerating for effect. I
am sure there is some benefit in m/c - like the ability to do crosswords
Regards
Richard Young
AST Teacher of Business Studies, Economics & ICT
Deputy Head of VI Form - Year 12
Wood Green School
Woodstock Road
Witney OX28 1DX
Tel 01993 702355
Fax 01993 774961
www.woodgreen.oxon.sch.uk
BECTa/Guardian Secondary School Web Site of the Year 2001
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-----Original Message-----
From: Economics, business, and related subjects
[mailto:[log in to unmask]] On Behalf Of Chris Rodda
Sent: 10 May 2003 13:59
To: [log in to unmask]
Subject: Re: Price Elasiticity of supply
Duncan - none of the above. Just a jaundiced comment about the state of
economics . My maths isn't great but mathematical proofs come in
various guises - the inductive - try a few calculations and come up
with a pattern and a rule, or use a deductive proof - usually a bit
harder. The inductive proof of course proves nothing but might be
useful, the deductive is rock solid. In economics we use both - or at
least we used to. It seems that more and more the deductive proofs are
being stripped away from A level economics, first indifference curves
then theory of the firm then the Keynesian cross, so that we are left
with the wish washy inductive stuff - discuss this in a role play etc..
Leaving us with something which doesn't deserve the title social
science any more.
Now it seems to me that once upon a time we might have tackled the
elasticity problem the hard way - I wonder if there are any students
out there that can manage that - it would be interesting to see.
PS Cambridge Spies was ***p - you should have slept.
Cheers
Chris :-)
On Saturday, May 10, 2003, at 11:11 AM, Duncan Williamson wrote:
> Chris,
>
> It's Saturday morning. I fought falling asleep in the chair from 9pm
> last
> night until the end of Cambridge Spies on BBC 4. I've already
> completed too
> many jobs including changing a fuse in the plug that drives an
> illuminated
> globe!
>
> So, did you just post a compliment, a brickbat or general words of
> support
> or denial? I didn't get it!!
>
> Sorry
>
>
> Duncan Williamson
>
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