Help needed with writing a formula

  • Thread starter Thread starter Karl
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K

Karl

I'm trying to complete an Excel 2000 model and I need some help with the
basic algebra.

Can someone please rewrite this for me to solve for P1?

A = ( P1+ P2 ) / ( 1+ ( R1 * ( D1 + D2 ) )

I know:

A = 99,200.881785616 (approx.)
P2 = 100,000.00
R1= 0.10 / 360 = 0.000277777778 (approx.)
D1= 31
D2= 29
and we know P1 will equal: 854.229815376 (approx.)


Additionally, can this be rewritten to solve for P2?

A = P2 / ( 1 + ( R1 * D2 ) )

Which, given the above value, P2 will again equal 100,000.00


Thanks a lot in advance. This would be a big help. I hate the idea of
cracking some text books that I've not looked at in 30 years!

Karl
 
Hi
I hope this is not homework :-)
1. P1 = A * [1+(R*(D1+D2))] - P2

2. P2 = A * [ 1+ (R1*D1)]
 
Hi Tom
I think the OP wanted the second formula to be solved for P2 (though I
wasn't sure either about this)
 
-----Original Message-----
I'm trying to complete an Excel 2000 model and I need some help with the
basic algebra.

Can someone please rewrite this for me to solve for P1?

A = ( P1+ P2 ) / ( 1+ ( R1 * ( D1 + D2 ) ) (Eq.1)

Additionally, can this be rewritten to solve for P2?

A = P2 / ( 1 + ( R1 * D2 ) ) (Eq.2)
Click to expand...

Yes; and Yes.


From Eq.1

A = P1 + P2
-------
1 + (R1 (D1 + D2))

so, as two responders have written,

P1 = A(1+R1(D1+D2)) - P2 (Eq.3)


From Eq.2

A= P2 / (1+ R1D1)

so, as you now know,

P2 = A(1+R1D2) (Eq.4)


However....

Substitute that value of P2 into Eq.3:

P1 = A(1+R1(D1+D2)) - A(1+R1D2)

Expand:

P1 = A + AR1D1 + AR1D2 - A - AR1D2

leaves

P1 = A.R1.D1

And Eq.4 expands to

P2 = A + A.R1.D2


Next question... what are the units ?

R1 (= 0.1/360) sounds like an angle in radians ?
i.e. a dimensionless ratio or pure number

So does P1 have the same units as A times D1 ?

Just checking....


RClay AT haswell DOT com
 
Thanks Tom and Frank. That was a big help. And I only wish it had been for
homework!


Frank Kabel said:
Hi
I hope this is not homework :-)
1. P1 = A * [1+(R*(D1+D2))] - P2

2. P2 = A * [ 1+ (R1*D1)]


--
Regards
Frank Kabel
Frankfurt, Germany
I'm trying to complete an Excel 2000 model and I need some help with
the basic algebra.

Can someone please rewrite this for me to solve for P1?

A = ( P1+ P2 ) / ( 1+ ( R1 * ( D1 + D2 ) )

I know:

A = 99,200.881785616 (approx.)
P2 = 100,000.00
R1= 0.10 / 360 = 0.000277777778 (approx.)
D1= 31
D2= 29
and we know P1 will equal: 854.229815376 (approx.)


Additionally, can this be rewritten to solve for P2?

A = P2 / ( 1 + ( R1 * D2 ) )

Which, given the above value, P2 will again equal 100,000.00


Thanks a lot in advance. This would be a big help. I hate the idea of
cracking some text books that I've not looked at in 30 years!

Karl
Click to expand...
Click to expand...
 
OK, using the second equation

A = P2 / ( 1 + ( R1 * D2 ) )

P2 = A * ( 1 + ( R1 * D2 ) )

And if that is True, then

P1 = A * (R1 * D1)
 
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