Show that the sum of an AP whose first term is a, the second term b and the last term c, is equal to (a+c)(b+c−2a)/2(b−a) is equal to (a+c)(b+c−2a)/2(b−a) Show that the sum of an AP whose first term is a the second term b and the last term c November 23, 2020 Category: Chapter [...]