brian bovril

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17 years, 30 days

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These are questions asked by brian bovril

I was trying some calculations for a solar installation.

4.9kW system. 3.5 h sun/day.  $0.27/kWh

                     "maple init loaded..."


but I want it to output 17.15 kWh/day

I looked up previous questions, and got this rather convoluted solution:

Units[AddSystem]( NewSI, Units[GetSystem](SI), kWh/day );
 Units[UseSystem]( NewSI ); 
combine( 4.9*Unit(kW)*3.5*Unit(h/day), units ); 



I found this paper.

I'm not sure if the population after 1 year is correct.

I wanted to get the formula from rsolve. But i have incorrorectly formulated the sum by day and the total.



If 0 occurs in the first element, I want to remove the list containing zero and the associated number.


p := [[[0, 5], [3, 10], [1, 20], [0, 50]], [[2, 5], [0, 10], [2, 20], [0, 50]]]

after processing:

[[[3, 10], [1, 20]], [[2, 5], [2, 20]]]

I tried in vain...

select(i -> (subs(p,p[1,i,1])>0), [$1..nops(p)]);

This latest question involves ELO, which is used to rate chess players (and other sports).

The difference between the previous (win-loss) system and ELO is the allowance for a third option, a draw. Carl coded the previous rating system, and I have tried to alter it.

See code for ELO procedure.

Adding a D to the third field, gets the result I want.

ELO(Record(rating= 2400),Record(rating= 2000),D)

Adding anything other than D to the third field means the first player defeats the second.

My preference would be to leave nothing in this third field to signify this (but I don't know if this is possible). 

The main problem is getting the bulk processing to work (for a series of matches...)

See Update procedure.

I have this flawed notation:

Games:= [[Tom_C, David_J, D],[David_J, Tom_C]]: #Tom_C drew David_J then David_J defeats Tom_C.

Hope someone can help.

Hi. I have an excel data file.

IDEALLY, I want to import the results of the formula in cells C3:C7.

But it doesn't like it. Reports 0's

When I convert the range to result to values in cells D3:D7 it imports no problem. But I don't want to do this step.

any ideas?





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