$[$EXERCISE USING EXCEL$]$ In class, we have talked about how the yield to maturity $($YTM$)$ can be calculated using Excel. Likewise, use the Excel file that has been uploaded on the web to answer the following questions.

Refer to the following bond quote from the Wall Street Journal $($WSJ$)$:

Date: $\frac{3}{29}\frac{?}{2017}$

$\backslash$table$[[$Security$,$Maturity,Coupon Rate,Price,Yield$],[$Treasury note,$\frac{3}{31}\frac{?}{2021},4\mathrm{.}50\%,104\mathrm{.}718,]]$

$($a$)$ Set up the present value equation.

$($b$)$ Solve the present value equation using Excel. That is$,$ calculate the yield to maturity $($YTM$)$ using Excel.

$($c$)$ Suppose that the frequency of payments is twice per year. How does the yield to maturity $($YTM$)$ change?