Consider the production function given as =(₁,₂)= ₁^3/6₂^2/4, where ₁ and ₂ refer to factor inputs 1 and 2, respectively.

1. With the aid of a scalar t (t > 1), prove whether this function exhibits increasing, decreasing or constant returns to scale

2. Apply partial differential calculus, to determine whether the above function exhibits diminishing marginal returns to factor x₁