Math Help Needed (1 Viewer)

davy17c

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Sons homework question.....Im now at a stage that I have no idea what this is about, 26 years after leaving the school and forgotten it all.

 
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There was a time when I knew how to answer that. Then I passed the test.
 

Zack Lee

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on a serious note, nothing goes away like math. When I was in school math was my best subject by far and included A's through to college Algebra classes. It just came natural. Last year I did an aptitude test when I first started thinking about going back and finishing and math was my weakest score. I was shocked at the stuff that stumped me, I just took it for granted that I was always good at it and always would be.


sorry to hijack but I know some showoff will be along 3,2,1...
 

Galbreath34

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Show off here.

First, f(g(x)) = (2x + p)^2 - 2.

Second g(f(x)) = 2 (x^2 - 2) + p.

Third ((2x + p)^2 - 2) - (2 (x^2 - 2) + p) can be expanded/simplified to the formula in the problem.

Someone else can hopefully help with b if you need more help from there.
 

buzd

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As far as I can tell, part b turns into a quadratic mess, unless I'm missing something.

Edit, nevermind, the value for p should be (-2).
 

LAhotsauce

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Show off here.

First, f(g(x)) = (2x + p)^2 - 2.

Second g(f(x)) = 2 (x^2 - 2) + p.

Third ((2x + p)^2 - 2) - (2 (x^2 - 2) + p) can be expanded/simplified to the formula in the problem.

Someone else can hopefully help with b if you need more help from there.
Old nested functions. ^^ this but watch your parenthesis and signs when simplifying. As for b? I require a happy ending or a free wax. Your choice.
 
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davy17c

davy17c

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Old nested functions. ^^ this but watch your parenthesis and signs when simplifying. As for b? I require a happy ending or a free wax. Your choice.
I can do tarmacing (nudge nudge wink wink)
 

buzd

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As far as I can tell, part b turns into a quadratic mess, unless I'm missing something.

Edit, nevermind, the value for p should be (-2).

To solve, use the quadratic function. We are only worried about the part under the square root, because that is what changes:

+/- root (b^2 - 4ac)

+/- root(16p^2 - 8*(p^2 - p +2) )

+/- root(8p^2 + 8p - 16)

Only time positive and negative roots are equal is when that is zero. Factor out and divide by 8.

p^2 + p - 2 = 0
(p+2)(p-1) = 0

p = (-2, 1)

After replacing back in, p=1 doesn't work. p=-2 does.

p=-2.
 
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davy17c

davy17c

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To solve, use the quadratic function. We are only worried about the part under the square root, because that is what changes:

+/- root (b^2 - 4ac)

+/- root(16p^2 - 8*(p^2 - p +2) )

+/- root(8p^2 + 8p - 16)

Only time positive and negative roots are equal is when that is zero. Factor out and divide by 8.

p^2 + p - 2 = 0
(p+2)(p-1) = 0

p = (-2, 1)

After replacing back in, p=1 doesn't work. p=-2 does.

p=-2.
Thank you :9:

Thank you one and all, well most.
 

HobBeh

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Somehow this the downfall of society


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