The characteristic constants ''A'' and ''B'' are the corresponding slope and the intercept of the straight line obtained from a Cartesian plot of the multiple rate test data ([[:file:fundamentals-of-fluid-flow_fig2.png|Figure 2c]]) in the following form: | The characteristic constants ''A'' and ''B'' are the corresponding slope and the intercept of the straight line obtained from a Cartesian plot of the multiple rate test data ([[:file:fundamentals-of-fluid-flow_fig2.png|Figure 2c]]) in the following form: |