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Kohe
Aug2-11, 06:21 PM
1. The problem statement, all variables and given/known data
f(x)= 1/(5x2 +3)
g(x)=1/(x-2)1/2

find (f+g)(x)


3. The attempt at a solution

for (f+g)(x) I use the common denominator by multiplying each side by (x-2)1/2/(x-2)1/2 and (5x2 +3/5x2 +3) respectively.

I end up with a whole mess that I am unable to rearrange into anything useful, the (x-2)1/2 completely throws me off my game.

Any ideas?

ArcanaNoir
Aug2-11, 07:46 PM
\frac{\sqrt{x-2}}{(\sqrt{x-2})(5x^2+3)}+\frac{5x^2+3}{(\sqrt{x-2})(5x^2+3)}=
\frac{(\sqrt{x-2})+(5x^2+3)}{(\sqrt{x-2})(5x^2+3)}

Isn't that what it is?

Kohe
Aug3-11, 04:34 AM
Same answer as me, I guess we can't be both wrong.

How about (f x g)(x)?

eumyang
Aug3-11, 04:41 AM
Why don't you show us, and then we'll let you know if it is correct.

Kohe
Aug3-11, 05:03 AM
\frac{\sqrt{x-2}}{(\sqrt{x-2})(5x^2+3)}+\frac{5x^2+3}{(\sqrt{x-2})(5x^2+3)}=
\frac{(\sqrt{x-2})+(5x^2+3)}{(\sqrt{x-2})(5x^2+3)}

Isn't that what it is?

Thanks for the help, for some reason I thought I could further simplify that.

So for (f x g)(x)

It'd be

1/(5x2+3) x 1/(x-2)1/2=

1/(5x2)*(x-2)1/2 + 1/3((x-2)1/2

That's where my problem lies, I have forgotten how to deal with the root of x-2 when trying to simplify this further. Also, as I'm new to the site, could one of you point me to the equation editor you guys use in your posts? It makes everything look a lot neater and easier to understand.

eumyang
Aug3-11, 05:43 AM
So for (f x g)(x)

It'd be

1/(5x2+3) x 1/(x-2)1/2=

1/(5x2)*(x-2)1/2 + 1/3((x-2)1/2
You don't need to do that last step. What you had previous to that is sufficient:
\frac{1}{\sqrt{x - 2}(5x^2 + 3)}

ArcanaNoir
Aug3-11, 05:58 AM
Also, as I'm new to the site, could one of you point me to the equation editor you guys use in your posts? It makes everything look a lot neater and easier to understand.

We type it using Latex. You should be able to see the original text if you hover or right click I think. You start with [ tex ] (without the spaces) and end with [/ tex] use itex if you want the equations to appear in line with regular text.

Kohe
Aug3-11, 07:03 AM
You guys have been great help, thank you all very much. I'll try to contribute towards answers as well once I get back in gear!