(Requires Calculus)For the Case of the Multiple Regression Problem with Two

question 30

Essay

(Requires Calculus)For the case of the multiple regression problem with two explanatory
variables, show that minimizing the sum of squared residuals results in three conditions: $$\sum _ { i = 1 } ^ { n } \widehat { u _ { i } } = 0 ; \sum _ { i = 1 } ^ { n } \widehat { u _ { i } } X _ { 1 i } = 0 ; \sum _ { i = 1 } ^ { n } \widehat { u _ { i } } X _ { 2 i } = 0$$