Business cycle analysis most commonly describes economic activity that is conducted through: A state enterprises. B agricultural co-ops. C private corporations. 按答案说的这题是不是应该选a？

这题为森么选A 答案数字没看明白

这道题C选项怎么就成错误的了？遵守业绩展示怎么就不对呢？

不懂

请问老师AB选项为什么不对呢？ 为什么C是对的？

AD曲线纵轴利率，那么利率下降ad下降，这么想为什么不对？

请问为什么不带上前面的1/2呢？

Mittal Tine’s investment portfolio currently consists of stocks in two companies, 40% in Drysdale Banking and the remaining amount in Clamped Oil. Performance measurement information for these two stocks is given in the table below: The covariance between the two stocks is 0.001. Tien is considering adding a third stock, Hillbillies Investors. Hillbillies Investor’s correlation coefficient with the current portfolio is 0.38. Which of the following statements is least accurate? A With Hillbillies added to the portfolio, the variance could be 0.026. B As Tien diversifies, he will reduce the portfolio's unsystematic risk. C The standard deviation of returns for the current portfolio is 15.5%. 这题答案错了吧，因该是w的平方乘以方差+w的平方乘以方差+2倍w1w2方差1方差2肉12

经常账户和资本账户是此消彼长的关系吗？经常账户赤字就一定是因为资本账户surplus吗？跟净出口没关系吗？

a是定义吗？c怎么不对，c看起来很好呀