The derivative of cosec x is
A
tan x cosec x
B
-cot x cosec x
C
tan x sec x
D
-cot x sec x
Verified Correct Answer: B.
Step-by-Step Mathematical Solution
\(\csc x = \frac{1}{\sin x}\)
Using the quotient rule,
\(\frac{\mathrm d y}{\mathrm d x} = \frac{vdu - udv}{v^{2}}\)
= \(\frac{\sin x (0) - 1 (\cos x)}{(\sin x)^{2}}\)
= \(\frac{- \cos x}{\sin^{2} x}\)
= \((\frac{- \cos x}{\sin x}) (\frac{1}{\sin x})\)
= \(- \cot x \csc x\)
Source: Myschool Past Questions Archive (Record #30940)