1. **Stating the problem:** We are given the salvage value function $$S(t) = 700000(0.8)^t$$ which represents the value of the jet after $$t$$ years. 2. **Find the rate of depreciation after 1 year:** The rate of depreciation is the rate of change of the salvage value, which is the derivative $$S'(t)$$. 3. **Calculate the derivative:** $$S'(t) = 700000 \cdot \frac{d}{dt} (0.8)^t = 700000 \cdot (0.8)^t \ln(0.8)$$ 4. **Evaluate at $$t=1$$:** $$S'(1) = 700000 \cdot (0.8)^1 \cdot \ln(0.8) = 700000 \cdot 0.8 \cdot \ln(0.8)$$ 5. **Calculate numerical value:** $$\ln(0.8) \approx -0.223143551$$ $$S'(1) = 700000 \cdot 0.8 \cdot (-0.223143551) \approx -124360$$ 6. **Interpretation:** The negative sign indicates depreciation. The rate of depreciation is approximately $$124360$$ dollars per year after 1 year. **Final answer:** The rate of depreciation after 1 year is approximately **124360** dollars per year.