I lost the biggest fish of my life (carp) ripped the hook off. How to tie 50lb line on hooks for carp?

I agree that a net would be a good idea BUT your suggestion of using 50lb test line will give you problems. Firstly the diameter of 50lb test is likely to be too wide to fit through the standard small hook eye that you would use for carp. Secondly the large diameter and stiffness of 50lb line is likely to fish your bait unnaturally and spook the fish due to the resistance caused by the line. Yes the palomar knot would work but the diameter of line would stop you from catching. All i can suggest is use a braided line in about 20-30lb test as this has a very low diameter then a fluorocarbon leader attached to this in about 18lb test. A leader of about 6ft should work. A net would also help you land the fish, along with setting your drag and using a rod with some flex as this would absorb the shock of any runs.

i agree with the polymar knot.. i use 4 pound test and have had zero breaks while fighting the fish. i use that knot on all test lines for that reason-- two loops around the eye. less stress.