ABSTRACT
For the formulas to work, we must keep the signs straight and be aware of what direction we mean as being positive.
If the differences are made very small, then we have:
If T=T2 T1 is dx
If T = T2 T1 is positive then dQ/dt comes out negative, i di ti th
negative then dQ/dt comes out positive, indicating the direction of heat flow is in the positive x direction.
