I recently replaced my hot water heater. THe new one was taller than the old one so I had to cut the pipes and shorten them. I had to use solder on fitting with a brass nut on the top end and a male fitting on the bottom. I have a leak right at the joint and have tried teflon tape, "pipe dope" and electrical tape? It still has the same small steady drip to it that it did before. The hot water out side has the same fitting but is not leaking. It did at first but has since quit. Any help or guidance on this matter is greatly appreciated

So you used an IP into the tank and a "nut"-(compression fitting?) to the pipe? If it is leaking at the pipe fitting, you will need to tighten it more. The reason the other side stopped is that the brass cold flowed to the shape of the female fitting. Turn off the water, release the pressure, loosen the conpression fitting and thighten the pipe fitting. I run into this occasionally when using a sharkbite IP into an SS ball valve.