How does one evaluate the form d(theta) on the circle?
I know a form takes a tangent vector X and spits out a real number , in a linear way. The tangent space to S^1 is R^1, so that a tangent vector is of the form c ; any non-zero real number can be a basis.
But, how do we get a number from d(theta)[c]?
I tried using a change of coordinate, changing from cartesian to polar, but I don't see much difference.