Re: Transposition problem

It would be more clear if you used brackets.

Is it:

$\displaystyle F=\frac{u\cdot v}{u+v}$ or $\displaystyle F=\frac{u\cdot v}{u}+v$

?

Re: Transposition problem

Quote:

Originally Posted by

**wysiwyg** Hello everyone.

I have just started a new college course which involves an analyticalmethods module. We have just started transposition and have been given thefollowing:

**F=uv/u+v**

I assume you mean F= uv/(u+v), not F= (uv/u)+ v since the latter would be just 2v.

Quote:

Transpose to find v

I have racked by brain for a bit and came up with..

**v=f/u-u**

Is this right? not sure if I have it right, can anyone help out?

Thanks in advance.

No, that is not correct. If you multiply both sides by u+ v, you get F(u+ v)= uF+ vF= uv.

Then uF= uv- vF= v(u- F). Can you finish it?

Re: Transposition problem

Quote:

Originally Posted by

**Siron** It would be more clear if you used brackets.

Is it:

$\displaystyle F=\frac{u\cdot v}{u+v}$ or $\displaystyle F=\frac{u\cdot v}{u}+v$

?

Apologies, I should have used brackets.

Its the first one...

Re: Transposition problem

No problem.

HallsofIvy has given you a hint. Can you continue? ...

Re: Transposition problem

Thanks guys, just trying to work through it now...

Bit confused with the two sets of equal signs tho i.e F(u+ v)**=** uF+ vF**=** uv

Unless I am reading it wrong...

Re: Transposition problem

If we start with:

$\displaystyle F=\frac{uv}{u+v}$

Step 1: Multiply both sides with $\displaystyle u+v$ (like HallsofIvy said):

$\displaystyle F(u+v)=uv$

Step 2: Work the brackets out:

$\displaystyle Fu+Fv=uv \Leftrightarrow Fu=uv-Fv \Leftrightarrow Fu=v(u-F)\Leftrightarrow v=...$

Is this clear? ...

Re: Transposition problem

Quote:

Originally Posted by

**Siron** If we start with:

$\displaystyle F=\frac{uv}{u+v}$

Step 1: Multiply both sides with $\displaystyle u+v$ (like HallsofIvy said):

$\displaystyle F(u+v)=uv$

Step 2: Work the brackets out:

$\displaystyle Fu+Fv=uv \Leftrightarrow Fu=uv-Fv \Leftrightarrow Fu=v(u-F)\Leftrightarrow v=...$

Is this clear? ...

Yes it is, thank you...

Is it: v=Fu/(u-F) ?

Re: Transposition problem

Re: Transposition problem

Thank you for your help (Siron/HallsofIvy), much appreciated.

Re: Transposition problem