jc.int

ok, I've understood the answer. Thank you very much for your help, Jaime

In this case, wouldn'y it be the cosine? If you look at this graph, where [bC] is the board, it seems that the projection of the area onto the perpendicular surface is the cosine,isn't it?

Thank you for your reply, can you explain me why do you use the sine of the angle? Jaime

hello, I'd like to know how does the solar radiation received on a flat surface vary if we change the angle of it. To simplify, if I've got a board of 1*1meters (at 0º -parallel to the ground-) and it is receiving 1Kw/h, the sun being at 90º, how will it received if I turn it 10º? Thank you Jaime

Thank you for your answer, I didn't thought that it would be interesting to comparemy problem with the Euler path. Do you know if there is a computer program that could help me find the answer (I've found this but it isn't really what I'm searching for as it passes through all the vectors I draw (http://www.math.okstate.edu/~wrightd/1493/euler/)? By the way the best circuit is the one that uses the least lenght of connection. Happy new year

Hello, I have thought of this math problem I haven't been able to solve, but it must have a simple solution. We have an undefined (either even or odd) number of line segments and we want to connect their end dots except two of them (for all the set -like if a fluid could get in by the unconnected dot, pass through all the segments and connections and them go out by the other unconnected dot).But there is an imposition: the connection cannot connect two segments that are side by side. Here is an uncompleted sketch -How can we know wherever it is better to have an odd number of line segments or an even one as to use the less length of connection? -What is, then, the best disposition of the connections (two by two and then the last one connects with the first one, three by three, etc)? I guess the way to solve this problem is to create a Cartesian model of it, but I don't know what to do then. Merry Christmas Jaime