Questions: Differentiate the following: f(x) = sec^(-1)(7x^3)
Transcript text: Differentiate the following: $f(x)=\sec ^{-1}\left(7 x^{3}\right)$
Solution
Solution Steps
To differentiate the function \( f(x) = \sec^{-1}(7x^3) \), we will use the chain rule and the derivative of the inverse secant function. The derivative of \( \sec^{-1}(u) \) with respect to \( u \) is \( \frac{1}{|u|\sqrt{u^2 - 1}} \). We will also need to differentiate the inner function \( 7x^3 \).
Step 1: Define the Function
We start with the function \( f(x) = \sec^{-1}(7x^3) \). To differentiate this function, we will apply the chain rule and the derivative of the inverse secant function.
Step 2: Differentiate the Function
Using the derivative of the inverse secant function, we have:
\[
f'(x) = \frac{1}{|u|\sqrt{u^2 - 1}} \cdot \frac{du}{dx}
\]
where \( u = 7x^3 \) and \( \frac{du}{dx} = 21x^2 \). Thus, we can express the derivative as:
\[
f'(x) = \frac{21x^2}{|7x^3|\sqrt{(7x^3)^2 - 1}} = \frac{21x^2}{7|x^3|\sqrt{49x^6 - 1}} = \frac{3}{|x|^4\sqrt{49x^6 - 1}}
\]
Final Answer
The derivative of the function \( f(x) = \sec^{-1}(7x^3) \) is given by:
\[
\boxed{f'(x) = \frac{3}{7x^4\sqrt{49x^6 - 1}}}
\]