Step 1: Define the function.
We are given the function:
\[
f(x) = x^2
\]
Step 2: Calculate \( f(1.1) \) and \( f(1) \).
We have:
\[
f(1.1) = (1.1)^2 = 1.21, \quad f(1) = (1)^2 = 1
\]
Step 3: Compute the expression.
Now, substitute into the given expression:
\[
\frac{f(1.1) - f(1)}{1.1 - 1} = \frac{1.21 - 1}{0.1} = \frac{0.21}{0.1} = 2.1
\]
Step 4: Conclusion.
The value of the expression is:
\[
\boxed{2.1}
\]