Circular reference

[Musashi]

I've searched and searched, but to no avail. Mayhap someone here is m
final hope.

I have an iterative formula which is as follows:

T=SIN(T)+6.023*T^0.4

Excel's circular reference gives me back T=0. I've deduced that that i
the only answer possible if Excel starts off assuming T=0 (SIN(0)=
and 0^0.4=0, then 0+0=0). Is there any form of getting Excel to us
another starting value for it's circular reference/iterative process?
If not, then what's the use of having such a flawed function which wil
falsify certain calculations?

Many thanks in advance to those that might be able to help me

 

[FxM]

Musashi < a écrit :

I've searched and searched, but to no avail. Mayhap someone here is my
final hope.

I have an iterative formula which is as follows:

T=SIN(T)+6.023*T^0.4

Excel's circular reference gives me back T=0. I've deduced that that is
the only answer possible if Excel starts off assuming T=0 (SIN(0)=0
and 0^0.4=0, then 0+0=0). Is there any form of getting Excel to use
another starting value for it's circular reference/iterative process?
If not, then what's the use of having such a flawed function which will
falsify certain calculations?

Many thanks in advance to those that might be able to help me.

Concerning circular reference, have a look in tools | options | you can
define a max number of iterations to be done.
Otherwise and if not too much calculations, use different cells
(A2 is results of calculations with A1)
(A3 is results of calculations with A2)
(A4 is results of calculations with A3), etc

If your results are not correct, check the following :
- internal Excel calculations are made in radians. Are radians the
correct units for your sin(...) ?
- is it ...+(6.023*T)^0.4 or ...+6.023*(T^0.4) ?
- is T the absolute temp (K) or relative temp (°C for ex)
- ...

@+
FxM

 

[Musashi]

With all of this I have played. The calculations are in fact in radians
so there is no problem there. Also, the number of iterations are no
worth touching if the starting value is 0. I guess then I'll have t
resort to adding 20+ columns to the sheet to to the iteration the ol
fashioned way. Thanks anyway

 

[Iain King]

Don't know if it's outputing the correct answer, but I tried this and it
seems to work:

(substituting A1 for T)

=IF(A1=0,1,SIN(A1)+6.023*A1^0.4)

Of course, if the answer is supposed to be zero then the loop will never
end, as it will switch to 1 whenever it equals 0. You are working in
radians - does this mean that 0 is equivalent to 2*Pi? If so, just change
the '1' to 2*Pi:

=IF(A1=0,Pi()*2,SIN(A1)+6.023*A1^0.4)

Iain