Here are some practice problems focused on finding the linear approximation of a function at a specified point:

1. Basic Linear Approximation
   Find the linear approximation to the function $f(x) = x^2$ at the point $a = 3$.

2. Trigonometric Function
   Find the linear approximation to the function $f(x) = \sin(x)$ at $a = \frac{\pi}{4}$.

3. Exponential Function
   Find the linear approximation to the function $f(x) = e^x$ at $a = 0$.

4. Logarithmic Function
   Find the linear approximation to the function $f(x) = \ln(x)$ at $a = 1$.

5. Radical Function
   Find the linear approximation to the function $f(x) = \sqrt{x}$ at $a = 4$.

Let me know if you would like the answers or further guidance on any of these problems!

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Here are some related practice questions:

1. How would the linear approximation change if we picked a different point $a$ for the function $f(x) = x^2$?
2. Why is the linear approximation useful for estimating the values of $\sin(x)$ near $x = \frac{\pi}{4}$?
3. What is the tangent line approximation to $f(x) = e^x$ near $a = 0$?
4. How accurate is the linear approximation for $f(x) = \ln(x)$ near $a = 1$?
5. How could the linear approximation for $f(x) = \sqrt{x}$ be used to approximate values near $x = 4$?

Tip: Remember, the linear approximation formula is $L(x) = f(a) + f'(a)(x - a)$, where $f'(a)$ is the derivative of the function evaluated at the point $a$.