The number of tangents to the curve \(xy-3y+2=0\) having slope 2 is:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → 2
The number of such tangents is the number of points on the curve where dy/dx = 2. From the equation of the curve,
\(y(x - 3) = -2\)
\( \displaystyle y = -\frac{2}{x - 3} \)
\( \displaystyle \frac{dy}{dx} = \frac{2}{(x - 3)^2} \)
Setting the slope equal to 2:
\( \displaystyle \frac{2}{(x - 3)^2} = 2 \)
\((x - 3)^2 = 1,\quad x = 4 \text{ or } x = 2\)
The points are (4, −2) and (2, 2). The tangents there are \(y = 2x - 10\) and \(y = 2x - 2\), two different lines. So there are 2 tangents with slope 2.