Question Detail

MTH 102 MTH 102 Past Questions Objective Question

Question

If y = esin2x / cos2x, find dy/dx. (Assume esinx in options is esin2x)
Options
A <i>dy/dx = 2e<sup>sin2x</sup> [1 - sec<sup>2</sup>x tan2x]</i>
B <i>dy/dx = 2e<sup>sin2x</sup> [1 - sec<sup>2</sup>x cos2x]</i>
C <i>dy/dx = 2e<sup>sin2x</sup> [1 + sec2x tan2x]</i>
Correct Answer
D <i>dy/dx = 2e<sup>sin2x</sup> [1 + sec2x cos2x]</i>
Correct Answer

Option C is the correct answer.

Detailed Explanation

Rewrite the function as y = esin2x · sec(2x) and use the product rule (uv)' = u'v + uv'.Let u = esin2x, then u' = esin2x · (d/dx(sin2x)) = esin2x · (cos2x · 2) = 2cos2x · esin2x.Let v = sec(2x), then v' = sec(2x)tan(2x) · (d/dx(2x)) = 2sec(2x)tan(2x).Apply the product rule:dy/dx = (2cos2x · esin2x) · sec(2x) + esin2x · (2sec(2x)tan(2x))Since sec(2x) = 1/cos(2x), the first term simplifies:dy/dx = 2cos2x · esin2x · (1/cos2x) + 2esin2xsec(2x)tan(2x)dy/dx = 2esin2x + 2esin2xsec(2x)tan(2x)Factor out 2esin2x:dy/dx = 2esin2x (1 + sec2x tan2x).

Hint

Rewrite the function using 1/cos(x) = sec(x) and then apply the product rule. Remember the chain rule.

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