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.
Differences between arteries and veins. arteries are larger, more muscular and more elastic than veins; they carry blood that is under pressure from having been pumped out of the heart; veins are under much less pressure, so they are not as strong.rtery Structure. arteries have three layers: a smooth inner layer; a strong, muscular layer; and a thin outer layer; connective fibers in artery walls allow for the elasticity needed for the artery to function; arteries are usually larger than veins.