7.1 The fuel-cost curves for two generators are given as follows:
$C_1(P_1) = 600 + 18 \cdot P_1 + 0.04 \cdot (P_1)^2$
$C_2(P_2) = 700 + 20 \cdot P_2 + 0.03 \cdot (P_2)^2$
Assuming the system is lossless, calculate the optimal dispatch values
of $P_1$ and $P_2$ for a total load of 1000 MW, the incremental operating
cost, and the total operating cost.