问题如下图：
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解释：
这道题我想的是，相关性变大，Var（DC）变大，相当于说风险增大了，如果风险越大意味着收益也越大，所以return会增加......这个角度理解有问题么......
NO.PZ2018111501000007 问题如下 If the correlation between foreign-currenasset returns anmovements in the exchange rate is increasing, the expectemestic-currenreturns will: increase crease unchange. C is correct.考点CurrenRisk Portfolio Return anRisk解析correlation的增加会影响mestic-currenrisk，而不会影响returns。写出公式就能理解了R=(1+RFC)(1+RFX)−1R_{}=(1+R_{FC})(1+R_{FX})-1R=(1+RFC)(1+RFX)−1 ，σ2(R)≈σ2(RFC)+σ2(RFX)+2σ(RFC)σ(RFX)ρ(RFC,RFX)\sigma^2(R_{})\approx\sigma^2(R_{FC})+\sigma^2(R_{FX})+2\sigma(R_{FC})\sigma(R_{FX})\rho(R_{FC},R_{FX})σ2(R)≈σ2(RFC)+σ2(RFX)+2σ(RFC)σ(RFX)ρ(RFC,RFX) 请问老师，Rfc和Rfx相关性增大，对R完全不产生影响，还是产生影响不确定，可能变大也可能变小？
NO.PZ2018111501000007 问题如下 If the correlation between foreign-currenasset returns anmovements in the exchange rate is increasing, the expectemestic-currenreturns will: increase crease unchange. C is correct.考点CurrenRisk Portfolio Return anRisk解析correlation的增加会影响mestic-currenrisk，而不会影响returns。写出公式就能理解了R=(1+RFC)(1+RFX)−1R_{}=(1+R_{FC})(1+R_{FX})-1R=(1+RFC)(1+RFX)−1 ，σ2(R)≈σ2(RFC)+σ2(RFX)+2σ(RFC)σ(RFX)ρ(RFC,RFX)\sigma^2(R_{})\approx\sigma^2(R_{FC})+\sigma^2(R_{FX})+2\sigma(R_{FC})\sigma(R_{FX})\rho(R_{FC},R_{FX})σ2(R)≈σ2(RFC)+σ2(RFX)+2σ(RFC)σ(RFX)ρ(RFC,RFX) 老师，如果相关性上升，不就意味着两者同涨或者同跌，感觉公式，同涨会使R上升，如果同跌，那负负得正，不也会使R上升
NO.PZ2018111501000007 问题如下 If the correlation between foreign-currenasset returns anmovements in the exchange rate is increasing, the expectemestic-currenreturns will: increase crease unchange. C is correct.考点CurrenRisk Portfolio Return anRisk解析correlation的增加会影响mestic-currenrisk，而不会影响returns。写出公式就能理解了R=(1+RFC)(1+RFX)−1R_{}=(1+R_{FC})(1+R_{FX})-1R=(1+RFC)(1+RFX)−1 ，σ2(R)≈σ2(RFC)+σ2(RFX)+2σ(RFC)σ(RFX)ρ(RFC,RFX)\sigma^2(R_{})\approx\sigma^2(R_{FC})+\sigma^2(R_{FX})+2\sigma(R_{FC})\sigma(R_{FX})\rho(R_{FC},R_{FX})σ2(R)≈σ2(RFC)+σ2(RFX)+2σ(RFC)σ(RFX)ρ(RFC,RFX) 根据公式，Rfc和Rfx都在上升，那R不是也在上升吗？R=（1+Rfc）*（1+Rfx）-1，前两项都变大，则R不应该也变大吗？
NO.PZ2018111501000007 问题如下 If the correlation between foreign-currenasset returns anmovements in the exchange rate is increasing, the expectemestic-currenreturns will: increase crease unchange. C is correct.考点CurrenRisk Portfolio Return anRisk解析correlation的增加会影响mestic-currenrisk，而不会影响returns。写出公式就能理解了R=(1+RFC)(1+RFX)−1R_{}=(1+R_{FC})(1+R_{FX})-1R=(1+RFC)(1+RFX)−1 ，σ2(R)≈σ2(RFC)+σ2(RFX)+2σ(RFC)σ(RFX)ρ(RFC,RFX)\sigma^2(R_{})\approx\sigma^2(R_{FC})+\sigma^2(R_{FX})+2\sigma(R_{FC})\sigma(R_{FX})\rho(R_{FC},R_{FX})σ2(R)≈σ2(RFC)+σ2(RFX)+2σ(RFC)σ(RFX)ρ(RFC,RFX) 这里说道的mestic risk↑，能不能等价于foreign risk也↑呢
NO.PZ2018111501000007问题如下 If the correlation between foreign-currenasset returns anmovements in the exchange rate is increasing, the expectemestic-currenreturns will: increase crease unchange. C is correct.考点CurrenRisk Portfolio Return anRisk解析correlation的增加会影响mestic-currenrisk，而不会影响returns。写出公式就能理解了R=(1+RFC)(1+RFX)−1R_{}=(1+R_{FC})(1+R_{FX})-1R=(1+RFC)(1+RFX)−1 ，σ2(R)≈σ2(RFC)+σ2(RFX)+2σ(RFC)σ(RFX)ρ(RFC,RFX)\sigma^2(R_{})\approx\sigma^2(R_{FC})+\sigma^2(R_{FX})+2\sigma(R_{FC})\sigma(R_{FX})\rho(R_{FC},R_{FX})σ2(R)≈σ2(RFC)+σ2(RFX)+2σ(RFC)σ(RFX)ρ(RFC,RFX) • If the correlation 0, then Rec returns are amplifieRey returns, anit willin turn increases mestic investor's return volatility.• If the correlation 0, then Rec returns are mpeneRey returns, anitwill in turn creases mestic investor's return volatility.
