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## #1 2005-12-29 00:09:35

Anne54321
Guest

### Equation help

Hi

If MARGIN+PICNUM*(MARGIN+WIDTH)+MARGIN+WIDTH=PICW/2

then WIDTH= ?

Thanks

## #2 2005-12-29 01:14:56

mathsyperson
Moderator
Registered: 2005-06-22
Posts: 4,900

### Re: Equation help

MARGIN+PICNUM*(MARGIN+WIDTH)+MARGIN+WIDTH=PICW/2

Put the additional MARGIN+WIDTH inside the brackets by factorising:
MARGIN+(PICNUM+1)*(MARGIN+WIDTH)=PICW/2

Put the MARGIN on the right-hand side:
(PICNUM+1)*(MARGIN+WIDTH)=PICW/2-MARGIN

Divide by (PICNUM+1):
MARGIN+WIDTH=(PICW/2-MARGIN)/(PICNUM+1)

Take away MARGIN:
WIDTH=[(PICW/2-MARGIN)/(PICNUM+1)]-MARGIN

Why did the vector cross the road?
It wanted to be normal.

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## #3 2005-12-29 01:32:23

krassi_holmz
Real Member
Registered: 2005-12-02
Posts: 1,905

### Re: Equation help

Why not
w=(pw/2-m)/(pn+1)-m

IPBLE:  Increasing Performance By Lowering Expectations.

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## #4 2005-12-29 03:05:41

seerj
Member
Registered: 2005-12-21
Posts: 42

### Re: Equation help

MARGIN+PICNUM*(MARGIN+WIDTH)+MARGIN+WIDTH=PICW/2

Let m MARGIN  p PICNUM  x WIDTH   q PICW
Then

m+p*(m+x)+m+x=q/2

px+x=q/2 -m -pm -m

x ( p+1 )=q/2-2m-pm

x= (q-4m-2pm)/2*(p+1)

x= (q-2m*(2+p)) / (2*( p+1 ))

WIDTH=( PICW-2MARGIN*(2+PICNUM))/(2*( PICNUM+1))

Last edited by seerj (2005-12-29 03:06:42)

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## #5 2005-12-29 09:44:34

Anne54321
Guest

### Re: Equation help

I have tried these equations in a computer program and I don't think they're yielding the correct answers.

If you take

MARGIN+PICNUM*(MARGIN+WIDTH)+MARGIN+WIDTH=PICW/2

and then use say MARGIN=10,PICNUM=7,WIDTH=10 and use these numbers to derive PICW

and then use one of the WIDTH solution equations with these numbers inserted they don't balance up ( by my reckoning!) Am I at fault or are these solutions ( which all yield the same answers) missing something ? Is it maybe a question of operator precedence?

## #6 2005-12-29 11:01:31

krassi_holmz
Real Member
Registered: 2005-12-02
Posts: 1,905

### Re: Equation help

IPBLE:  Increasing Performance By Lowering Expectations.

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## #7 2005-12-30 10:07:09

Anne54321
Guest

### Re: Equation help

My mistake. It works perfectly. Many thanks for al your help. I've learnt a lot from you all.

## #8 2005-12-30 10:10:18

krassi_holmz
Real Member
Registered: 2005-12-02
Posts: 1,905

### Re: Equation help

You'll learn a lot from us.

IPBLE:  Increasing Performance By Lowering Expectations.

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