Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Applications of Derivatives

Question:
If the line \(ax+by+c=0\) is a normal to the curve \(xy=4\), then
Options:
\(a<0,b<0\)
\(a>0,b>0\)
\(a>0,b<0\)
\(a<0,b=0\)
Correct Answer:
\(a>0,b<0\)
Explanation:
\(y=-\frac{a}{b}x-\frac{c}{b}\) So, \(m=-\frac{a}{b}\hspace{6cm}\) Given \(xy=4\) So, \(\frac{dy}{dx}=-\frac{y}{x}\hspace{7cm}\) Slope of normal\(=\frac{x}{y}\hspace{8cm}\) Thus, \(\frac{x}{y}=-\frac{a}{b}\)