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#1 2014-08-06 23:09:47

thedarktiger
Member
Registered: 2014-01-10
Posts: 91

Minimum problem

Find all values of p such that 2(x+4)(x-2p) has a minimum value of -18.
Thanks


Good. You can read.

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#2 2014-08-06 23:27:24

Bob
Administrator
Registered: 2010-06-20
Posts: 10,056

Re: Minimum problem

hi thedarktiger

If the quadratic is of the form y = .....  then it will have a vertical line of symmetry.  ie. straight through the minimum point.

Here's an example:

ZLaX80d.gif

As you know the minimum y, and one of the roots, you should be able to form some equations to get the other.

Such as: Let the minimum point be at (q,18).

Then q must fit the equation and q is equidistant from -4 and 2p.

Bob


Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob smile

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#3 2014-08-06 23:42:26

Agnishom
Real Member
From: Riemann Sphere
Registered: 2011-01-29
Posts: 24,974
Website

Re: Minimum problem

That red-blue graphing tool looks familiar. what is it?


'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.

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#4 2014-08-07 00:24:03

Bob
Administrator
Registered: 2010-06-20
Posts: 10,056

Re: Minimum problem


Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob smile

Online

#5 2014-08-07 01:34:31

Agnishom
Real Member
From: Riemann Sphere
Registered: 2011-01-29
Posts: 24,974
Website

Re: Minimum problem

Thanks


'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'
'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'
I'm not crazy, my mother had me tested.

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