Given: a2 = a + d = ….. (1)
a6 = a + d = - ….. (2)
Solving equations (2) from (1) we get
Now substituting, d = – in equation (1), we get
a + (- ) = ⇒ a = + =
Thus,
a1 = a = ;
a3 = a + 2d = + × (- ) = – = ;
a4 = a + 3d = + × (- ) = – = ;
a5 = a + 4d = + × (- ) = – = –