Question Detail
Question
Find the derivative of \( y = \sqrt{x-1} \) at \( x=5 \).
Correct Answer
Option B is the correct answer.
Detailed Explanation
( y = (x-1)^{1/2} \implies y' = \frac{1}{2}(x-1)^{-1/2} ). At ( x=5, y' = \frac{1}{2}(4)^{-1/2} = \frac{1}{2} \cdot \frac{1}{2} = 1/4 ).
Hint
Apply the power rule for functions of the form \( u^{1/2} \).