From Equations (17 $$\text { temperature at which a heat pump can be effective) in terms of } R , A , P _ { i n } \text {, and } T _ { h } \text {. }$$

Essay

From equations (17.4) and (17.5), solve for Tc (i.e., the minimum $$\text { temperature at which a heat pump can be effective) in terms of } R , A , P _ { i n } \text {, and } T _ { h } \text {. }$$