Expected Square
1. **Problem statement:** Given a random variable $X$ with expected value $E[X] = 5$ and variance $\text{Var}(X) = 2$, find $E[X^2]$.
2. **Recall the formula for variance:**
$$\text{Var}(X) = E[X^2] - (E[X])^2$$
This formula relates the variance, the expected value of the square of $X$, and the square of the expected value of $X$.
3. **Rearrange the formula to solve for $E[X^2]$:**
$$E[X^2] = \text{Var}(X) + (E[X])^2$$
4. **Substitute the given values:**
$$E[X^2] = 2 + 5^2 = 2 + 25 = 27$$
5. **Interpretation:** The expected value of the square of $X$ is 27.
**Final answer:**
$$E[X^2] = 27$$