# Talk:Heated Bed Theory

Hello,

As I was working on a new bed design I noticed a small discrepancy between the board shown in the picture and the math behind it.

I based myself on the equations included on the entry when I found this out:

This is based on the equations available on the page, more specifically, $n_{tr}= \frac{W_b}{W_{tr}+W_i} \\ \\$

When using this formula I ended up having n horizontal tracks+ 1 residual vertical track (I tested this by programmatically generating my tracks in eagle) as opposed to exactly n tracks; In order to solve this I had to change the formula to the following: $n_{tr}= \frac{W_b}{W_{tr}+W_i} +1$

The reasoning behind it came from working it from the Wb side when I as trying to figure out why I was having this issue:

$\\ \\ W_b=n_{tr}(W_{tr}+W_i)-(W_{tr}+W_i) \\ W_b=(n_{tr}-1)(W_{tr}+W_i) \\ \frac{W_b}{W_{tr}+W_i}=n_{tr}-1 \\ \frac{W_b}{W_{tr}+W_i}+1=n_{tr} \\ \\$

Best Regards,