Referring to CFAI 2010 AM, question 5E, they ask: calculate the risk of Slifer’s investment in Chinese equities measured in U.S. dollar terms. Show your calculations.

Answer says: the variance of the returns on foreign asset in U.S. Dollar terms = variance of foreign asset in local currency + Variance of the exchange rate + (2 × correlation between Foreign asset return and exchange rate movement × standard deviation of foreign asset in local currency × standard deviation of the exchange rate) Where is this formula from? Is it still in 2015?