however, is not conservative. The natural question arises: why can we not apply the process of the previous example? The reason is that is not independent of the path, and hence (as in example 47.2.13) we cannot always select path parallel to the axes to integrals. Let us analyze this in detail. Let , for some in

Then

                                                                  ----------(46)

Hence, if we integrate, we get

This will give us