The arctangent is the inverse tangent function. Since. tan Ï/4 = tan 45Âº = 1. The arctangent of 1 is equal to the inverse tangent function of 1, which is equal to Ï/4 radians or 45 degrees: arctan 1 = tan-1 1 = Ï/4 rad = 45Âº. 1  Arctan.  Arctan calculator.
1 The difference is that an artery brings blood to the body and a vein takes blood to the lungs.  Arteries and Veins are part of the circulatory system, where arteries carry the blood from the heart to the organs, and the veins carry it from the organs to the heart again.
Besides color, another difference between arteries in veins is that arteries pulsate (expand and contract) much more than veins do as blood flows through them. The slight changes in the shape and size of our veins is so slight that you can't even feel it.