Question

If $y = \sec\, x^?$, then $\frac{dy}{dx}$ is equal to:

• A. $\sec\, x\, \tan \,x$
• B. $\sec \,x^?\, \tan \,x^?$
• C. $\frac{\pi}{180} \sec \,x^\circ \, \tan \, x^\circ$
• D. none of these

Answer 1

Answer: (C)

$\frac{\pi}{180} \sec \,x^\circ \, \tan \, x^\circ$

Answer 2

Let $y = \sec\, x?$ Now ,$x^\circ = \frac{\pi}{180} . x \:\:\: \therefore \: y =\sec \frac{\pi}{180} x$ Now, $\frac{dy}{dx} = \frac{\pi}{180} \sec \frac{x \pi}{180} \tan \frac{\pi}{180} x$ $\Rightarrow \:\: \frac{dy}{dx} =\frac{\pi}{180} \: \sec \, x^\circ . \tan \, x^\circ$