user: Extract the formulas in math latex markdown format to calculate the portfolio return and variance in Modern Portfolio Theory https://en.wikipedia.org/wiki/Modern_portfolio_theory

assistant: - Expected return:
$$
\mathrm{E}\left(R_p\right)=\sum_i w_i \mathrm{E}\left(R_i\right)
$$
where $R_p$ is the return on the portfolio, $R_i$ is the return on asset $i$ and $w_i$ is the weighting of component asset $i$ (that is, the proportion of asset "i" in the portfolio, so that $\sum_i w_i=1$ ).
- Portfolio return variance:
$$
\sigma_p^2=\sum_i w_i^2 \sigma_i^2+\sum_i \sum_{j \neq i} w_i w_j \sigma_i \sigma_j \rho_{i j}
$$
where $\sigma_i$ is the (sample) standard deviation of the periodic returns on an asset $i$, and $\rho_{i j}$ is the correlation coefficient between the returns on assets $i$ and $j$. Alternatively the expression can be written as:
$$
\sigma_p^2=\sum_i \sum_j w_i w_j \sigma_i \sigma_j \rho_{i j}
$$
where $\rho_{i j}=1$ for $i=j$, or
$$
\sigma_p^2=\sum_i \sum_j w_i w_j \sigma_{i j}
$$
where $\sigma_{i j}=\sigma_i \sigma_j \rho_{i j}$ is the (sample) covariance of the periodic returns on the two assets, or alternatively denoted as $\sigma(i, j)$, $\operatorname{cov}{ }_{i j}$ or $\operatorname{cov}(i, j)$.
- Portfolio return volatility (standard deviation):
$$
\sigma_p=\sqrt{\sigma_p^2}
$$
For a two-asset portfolio:
- Portfolio return: 
$$\mathrm{E}\left(R_p\right)=w_A \mathrm{E}\left(R_A\right)+w_B \mathrm{E}\left(R_B\right)=w_A \mathrm{E}\left(R_A\right)+\left(1-w_A\right) \mathrm{E}\left(R_B\right)$$

- Portfolio variance: 
$$\sigma_p^2=w_A^2 \sigma_A^2+w_B^2 \sigma_B^2+2 w_A w_B \sigma_A \sigma_B \rho_{A B}$$
For a three-asset portfolio:
- Portfolio return: 
$$\mathrm{E}\left(R_p\right)=w_A \mathrm{E}\left(R_A\right)+w_B \mathrm{E}\left(R_B\right)+w_C \mathrm{E}\left(R_C\right)$$
- Portfolio variance: 
$$\sigma_p^2=w_A^2 \sigma_A^2+w_B^2 \sigma_B^2+w_C^2 \sigma_C^2+2 w_A w_B \sigma_A \sigma_B \rho_{A B}+2 w_A w_C \sigma_A \sigma_C \rho_{A C}+2 w_B w_C \sigma_B \sigma_C \rho_{B C}$$

user: Identify which instrument is string or percussion: Igil, Bara

assistant: Bara is percussion, Igil is string.

user: Why do we have work meetings?

assistant: We have work meetings to give status updates on current projects.  These meetings can be virtual or in person.  In-person work meetings are great for building rapport, meeting new people, and building stronger relationships with people you already know.  Staying up to date on what everyone is working and aligning with company vision is how companies stay successful and have a competitive advantage over their competitors.  Regular meetings are the best way to achieve this.