20. [Growth] Assume a production function Y : K'J'N1_'\". (a) Show that the production function is constant returns to scale. Derive also y 2 k\" when y : Y/N and k = K /N . (b) Derive the following equation 16/]: : K / K n. where ' is the derivative in time t and N/N : n. (c) Derive k = ska (n + 6)}: when a xed amount ratio .5 of production Y is saved and all amount of saving is invested, where 6 is depreciation rate in capital. (d) Assume that 19* is capital per capita when k : 0. Show that k gradually decreases and converges to k* for any is > k'\" (e) Explain about 'The Golden Rule of Capital Accumulation