Prove that when the foreign tax rate exceeds the domestic rate, foreign investment is preferred to domestic investment, for any investment horizon, if and only if the after-local tax rate of return...

Prove that when the foreign tax rate exceeds the domestic rate, foreign investment is preferred to domestic investment, for any investment horizon, if and only if the after-local tax rate of return abroad exceeds the after-tax rate of return at home, rf > rd. Also prove that the same condition determines whether reinvestment abroad is preferred to repatriation of foreign earnings and profits.