Question Detail

MTH 102 MTH 102 Past Questions Objective Question

Question

Find \(\frac{d}{dx} (\csc^{-1}(5x))\).
Options
A \(\frac{1}{5x\sqrt{25x^2-1}}\)
B \(-\frac{1}{x\sqrt{25x^2-1}}\)
Correct Answer
C \(-\frac{5}{x\sqrt{25x^2-1}}\)
D \(-\frac{1}{5x\sqrt{25x^2-1}}\)
Correct Answer

Option B is the correct answer.

Detailed Explanation

The derivative of (\csc^{-1}(u)) with respect to (x) is (-\frac{1}{|u|\sqrt{u^2-1}} \cdot \frac{du}{dx}).Here, (u = 5x), so (\frac{du}{dx} = 5).Substituting these values:(\frac{d}{dx} (\csc^{-1}(5x)) = -\frac{1}{|5x|\sqrt{(5x)^2-1}} \cdot 5)(= -\frac{5}{5|x|\sqrt{25x^2-1}})(= -\frac{1}{|x|\sqrt{25x^2-1}}).Assuming (x>0), (|x|=x). Therefore, (= -\frac{1}{x\sqrt{25x^2-1}}).

Hint

Recall the derivative of \(\csc^{-1}(u)\) and apply the chain rule.

Question Info