Assume we have two plain vanilla bonds, both with a face value of $100.$ The first one has $1$ year to maturity and a coupon of $2\mathrm{.}5\%$ and trades at $99\mathrm{.}65,$ the second one maturing in two years, has a coupon of $3\mathrm{.}5\%$ and trades at $102\mathrm{.}00.$ Derive the spot yields r$\_1$ and r$\_2$ iteratively.