Answer is: option4
2Solution:
Step 1: Recall the inverse function derivative rule
If \( g \) is the inverse of \( f \), then the derivative of the inverse function at any point is given by the formula:
\[ (f^{-1})'(y) = \frac{1}{f'(f^{-1}(y))} \]
Step 2: Solve for \( f^{-1}\left(\frac{\sqrt{3}}{2}\right) \)
We need to find the value of \( x \) such that \( \sin x = \frac{\sqrt{3}}{2} \). This is a standard value from trigonometry. The solution for \( \sin x = \frac{\sqrt{3}}{2} \) is:
\[ x = \frac{\pi}{3} \]
Step 3: Find \( f'(x) \)
The derivative of \( f(x) = \sin x \) is:
\[ f'(x) = \cos x \]
Step 4: Evaluate \( f'\left(\frac{\pi}{3}\right) \)
Substitute \( x = \frac{\pi}{3} \) into \( f'(x) \):
\[ f'\left(\frac{\pi}{3}\right) = \cos\left(\frac{\pi}{3}\right) = \frac{1}{2} \]
Step 5: Apply the inverse function derivative formula
Now, apply the inverse function derivative formula:
\[ (f^{-1})'\left(\frac{\sqrt{3}}{2}\right) = \frac{1}{f'\left(\frac{\pi}{3}\right)} = \frac{1}{\frac{1}{2}} = 2 \]
Final Answer:
The value of \( (f^{-1})'\left(\frac{\sqrt{3}}{2}\right) \) is \( 2 \), so the correct answer is (D).