Mathematics

Mathematics

Problem

If y=tan⁡x+cot⁡xtan⁡x−cot⁡xy = \frac{\tan x + \cot x}{\tan x - \cot x}, then dydx=\frac{dy}{dx} = (a) 2tan⁡2xsec⁡2x2 \tan 2x \sec 2x (b) tan⁡2xsec⁡2x\tan 2x \sec 2x (c) −tan⁡2xsec⁡2x-\tan 2x \sec 2x (d) −2tan⁡2xsec⁡2x-2 \tan 2x \sec 2x
Intuitive explanation

This problem asks you to differentiate a trigonometric fraction—but before you dive into the quotient rule, simplify the expression first. Rewrite tan⁡x\tan x and cot⁡x\cot x in terms of sin⁡x\sin x and cos⁡x\cos x, combine the fractions in the numerator and denominator, and you'll discover the expression collapses into something much cleaner, likely a single trig function or a simple multiple of one. Once simplified, the derivative becomes straightforward.

Intuitive explanation

This problem asks you to differentiate a trigonometric fraction—but before you dive into the quotient rule, simplify the expression first. Rewrite tan⁡x\tan x and cot⁡x\cot x in terms of sin⁡x\sin x and cos⁡x\cos x, combine the fractions in the numerator and denominator, and you'll discover the expression collapses into something much cleaner, likely a single trig function or a simple multiple of one. Once simplified, the derivative becomes straightforward.

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