Schoolcrop

(Q13).Find the respective terms for the following APs.

(ii) a₂ = 13; a₄ = 3, find a₁, a₃.

Given: a₂ = a + d = ….. (1)

a₄ = a + 3d = ….. (2)

Solving equations (1) and (2);

⇒ a + 3d =

⇒ a + d =

d = -

⇒ d = -

∴ Substituting d = – in equation (1) we get

a + (-) = 13

∴ a = 13 + = i.e., a₁ =

a₃ = a + 2d = + 2(-)

= – =