Rearranging an equation with absolute values

seanehl

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Nov 21, 2012
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I'm trying to rearrange the following formula, and I'm just plain stuck:

s = F * abs(f - 0.5) + (1-F) * abs((0.5-F*f)/(1-F) - 0.5)

I've used 'abs' to denote 'absolute value of', just to be clear. Here, big 'F' and little 'f' are separate variables. I'd like to solve for this equation in terms of little 'f'. Any clue what the rearranged equation would be?

Thanks soo much for your help!! This is for some computer code that i'm writing for a college class, and it's challenging for me to try to rearrange this equation with absolute values...I've tried to read the rules for dealing with abs values, but i can't find anything that's really helpful.

Also, if it helps, F, f, and s cannot be negative numbers for my purposes.

Sean
 
Last edited:
I'm trying to rearrange the following formula, and I'm just plain stuck:

s = F * abs(f - 0.5) + (1-F) * abs((0.5-F*f)/(1-F) - 0.5)

I've used 'abs' to denote 'absolute value of', just to be clear. Here, big 'F' and little 'f' are separate variables. I'd like to solve for this equation in terms of little 'f'. Any clue what the rearranged equation would be?

Thanks soo much for your help!! This is for some computer code that i'm writing for a college class, and it's challenging for me to try to rearrange this equation with absolute values...I've tried to read the rules for dealing with abs values, but i can't find anything that's really helpful.

Also, if it helps, F, f, and s cannot be negative numbers for my purposes.

Sean

You need to read the rules of this forum. Please read the post titled "Read before Posting" at the following URL:

http://www.freemathhelp.com/forum/th...217#post322217


We can help - we only help after you have shown your work - or ask a specific question (not a statement like "Don't know any of these")

s = F * abs(f - 0.5) + (1-F) * abs((0.5-F*f)/(1-F) - 0.5)

s = F * abs(f - 0.5) + (1-F) * abs(-F(0.5+f)/(1-F))

according to your assumptions F(0.5+f) > 0

while solving 'abs' equation I break those down according to the values it can take. Here I see two possibilities:

s = F * (f - 0.5) - F*(0.5+f) when f> 0.5

s = - F * (f - 0.5) - F*(0.5+f) when 0<f<0.5

and continue...

Please share your work with us indicating exactly where you are stuck - so that we may know where to begin to help you.
 
Last edited by a moderator:
I'm trying to rearrange the following formula, and I'm just plain stuck:

s = F * abs(f - 0.5) + (1-F) * abs((0.5-F*f)/(1-F) - 0.5)

I've used 'abs' to denote 'absolute value of', just to be clear. Here, big 'F' and little 'f' are separate variables. I'd like to solve for this equation in terms of little 'f'. Any clue what the rearranged equation would be?

Thanks soo much for your help!! This is for some computer code that i'm writing for a college class, and it's challenging for me to try to rearrange this equation with absolute values...I've tried to read the rules for dealing with abs values, but i can't find anything that's really helpful.

Also, if it helps, F, f, and s cannot be negative numbers for my purposes.

Sean
If the conditions of the problem let you use a pre-coded absolute value function, then the problem is trivial. So I am supposing that you are not allowed to use a pre-coded absolute value function. But that means I am guessing, which is why you need to read and follow the read-before-posting guidelines.

In terms of coding, a different approach from Subhotosh Khan's is to calculate the arguments of the absolute values, and if they are negative, multiply them by minus 1. In coding, you can take an algorithmic approach rather than an equation approach.
 
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