### If a smooth curve begins at (a,c) and ends at (b,d), a<b, c<d, then the length of the curve is:
L= ∫(from a to b) √1+(dy/dx)∧2dx
If y is a smooth function of x on [a,b]
L= ∫(from c to d)√1+(dx/dy)^2dy
If x is a smooth function of y on [c,d]
***Remember: Smooth curves are continuous and differentiable***