求用matlab画几个超级简单的函数图, 需要程序代码：（每个图要有标题，每个轴要有标注，所有图的横轴都是W, W代表Wealth, U(W)代表Utility, R(W)代表Absolute Risk Aversion, R_r(W)代表Relative Risk Aversion）1. U(W)= -e^(-2W) 标题：Utility Function across Wealth with Negative Exponential Utility Function
2. R(W)=2 标题：Absolute Risk-aversion Function across Wealth with Negative Exponential Utility Function
3. R_r(W)=2W  标题：Relative Risk-aversion across Wealth with Negative Exponential Utility Function
4. U(W)=2W^(0.5) 标题：Utility Function across Wealth with Power Utility Function
5. R(W)=0.5/W  标题：Absolute Risk-aversion Function across Wealth with Power Utility Function
6. R_r(W)=0.5 标题：Relative Risk-aversion across Wealth with Power Utility Function