Problem

Consider the function $f(x)=3 \sqrt{x}-4$.
(a) Simplify the following difference quotient as much as possible
\[
\frac{f(4+h)-f(4)}{h}
\]
(b) Use your result from (a) and the limit definition of the derivative to calculate
\[
f^{\prime}(4)=\lim _{h \rightarrow 0} \frac{f(4+h)-f(4)}{h}=
\]
(c) Use your answer from part (b) to find the equation of the tangent line to the curve at the point $(4, f(4))$.
\[
y=
\]

Answer

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Answer

\(\boxed{y - 2 = \frac{3}{4}(x - 4)}\)

Steps

Step 1 :\(f(4+h) = 3\sqrt{4+h}-4\)

Step 2 :\(f(4+h) - f(4) = 3\sqrt{4+h}-4 - (3\sqrt{4}-4)\)

Step 3 :\(\frac{f(4+h)-f(4)}{h} = \frac{3\sqrt{4+h}-4 - (3\sqrt{4}-4)}{h}\)

Step 4 :\(f^\prime(4) = \lim_{h \rightarrow 0} \frac{f(4+h)-f(4)}{h} = \frac{3}{2\sqrt{4}}\)

Step 5 :\(y - 2 = \frac{3}{2\sqrt{4}}(x - 4)\)

Step 6 :\(\boxed{y - 2 = \frac{3}{4}(x - 4)}\)

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