Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Differential Equations

Question:
Equation of the curve passing through \((1,1)\) and satisfying the differential equation \(\frac{dy}{dx}=\frac{2y}{x}\) is given by \((x>0,y>0)\)
Options:
\(x^{2}=y\)
\(x=y^{2}\)
\(x=2y\)
\(y=2x\)
Correct Answer:
\(x^{2}=y\)
Explanation:
\(\begin{aligned}\frac{dy}{y}&=\frac{2dx}{x}\\ \text{So, }\log y&=2\log x+\log c\\ y&=x^{2}c\\ \text{Setting }x=1,y&=1\text{ we get }c=1\\ \text{Thus, }y&=x^{2}\end{aligned}\)