A manufacturer uses 10,000 units of a raw material per year. The ordering cost is $\\$100$per order, and the holding cost is$\$2$ per unit per year. The supplier offers a quantity discount: if the order quantity is $Q \\ge 2000$, the purchase price is $\\$9.50$per unit; otherwise, the price is$\$10.00$ per unit. What is the optimal order quantity $Q^*$ that minimizes the total annual cost (purchasing + ordering + holding)?