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Some Calculus

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Ace:

Well, not exactly, it's only part of my Calculus class, but over the summer I had completely forgotten almost everything I knew about mathematics and I could use a bit of a push. I'm stumped with this problem here:


--- Quote ---Solve for a:

     (1/a)+(1/b)=(1/c)

--- End quote ---

It seems that no matter which way I approach this problem, I always end up with cb=0, completely eliminating a due to one side coming down to "a-a" somehow. Clearly I'm doing something wrong here but I cannot pinpoint what it is.

I could be missing something completely obvious that could solve the problem quickly, who knows.

Ladios:

Try looking for the answer in the back of your book and working backwards from there?

Ace:


--- Quote from: ladios on August 30, 2009, 03:43:00 PM ---Try looking for the answer in the back of your book and working backwards from there?

--- End quote ---
It's on a worksheet. If it were in the book I would not have posted it here.

TheGeek:


--- Code: ---1/a + 1/b = 1/c
1/a = 1/c - 1/b = b/bc - c/bc = (b-c)/bc
a = bc/(b-c)
--- End code ---


* Get 1/a on the left side of the equation
* Change the right side to the same denominator
* Add up the right side
* Invert both sides of the equation

Ace:

Ah thank you, it seems surprisingly simple now. I hadn't thought of isolating 1/a first.

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