Given the function $f(x) = -x^2$, we want to find $f(-1)$.

Substitute $-1$ for $x$ in the function:

$f(-1) = -(-1)^2$

Calculate $(-1)^2$:

$(-1)^2 = 1$

So, the expression becomes:

$f(-1) = -1$

Thus, $f(-1) = -1$.

Would you like more details or have any questions?

Here are 5 related questions:

1. What is $f(2)$ for the function $f(x) = -x^2$?
2. How does the graph of $f(x) = -x^2$ differ from $f(x) = x^2$?
3. What is the vertex of the parabola represented by $f(x) = -x^2$?
4. How would you find the roots of the function $f(x) = -x^2$?
5. What is the range of the function $f(x) = -x^2$?

Tip: When substituting values into a function, always follow the order of operations, especially with negative numbers and exponents.