The answer is a I think that is correct
<span>The number of ways to permute three correct answers among five questions is 5Choose3 which is 5!/(3!*2!) which equals 10.
We must then have the correct answer three times which happens .25 of the time, and two wrong answers 75 of the time.
So the probability is 10*0.25^3*.75^2 which is 0.087890625 or roughly an 8.8% chance.</span>
The tangent line to the curve can be determined by implicitly differentiating the equation of the curve. In this case, with the equation <span>y sin 12x = x cos 2y, (π/2, π/4), the implicit differentiation is 12 y cos 12x dx + sin 12 x dy = -2x sin 2y dy + cos 2y dx; dx (12 y cos 12x - cos 2y) = dy (</span><span>-2x sin 2y - sin 12x). Hence
y' = (</span>12 y cos 12x - cos 2y) / (<span>-2x sin 2y - sin 12x)</span>
