Find ∫ DS, where l is the circle x2 + y2 = 4

Find ∫ DS, where l is the circle x2 + y2 = 4

Let's find ∫ DS, where l is a circle, where l is a circle, and the solution (1): DS is a differential of the arc length; DS = {(DX \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\check (...)