Question

Differentiate unit vectors of spherical coordinated

Answer 1

Derivatives of Unit Vectors in Spherical and Cartesian Coordinates. If one takes the derivative of with respect to (ignoring the -dependence of the spherical unit vectors), one gets the expression for . Similarly, taking the partial derivative of with respect to and setting to , yields the expression for .

Answer 2

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Polyester Filters are made on a master roll, the colour being coated onto the surface of the clear polyester base material. Because the filters are very thin (0.1mm) the optical quality is high. Polyester is a good, low cost alternative to Resin, but because of the manufacturing process polyester grads are not available.

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