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Let us consider a curve, y=f(x) passing through the point (-2,2) and the slope of the tangent to the curve at any point (x, f(x)) is given by f(x)+x f^{\prime}(x)=x^{2}. Then:
Option: 1 x^{2}+2 x f(x)-12=0
Option: 2 x^{2}+2 x f(x)-12=0
Option: 3 x^{2}+2 x f(x)-12=0
Option: 4 x^{2}+2 x f(x)-12=0
Option: 5 x^{3}-3 x f(x)-4=0
Option: 6 x^{3}-3 x f(x)-4=0
Option: 7 x^{3}-3 x f(x)-4=0
Option: 8 x^{3}-3 x f(x)-4=0
Option: 9 x^{3}+x f(x)+12=0
Option: 10 x^{3}+x f(x)+12=0
Option: 11 x^{3}+x f(x)+12=0
Option: 12 x^{3}+x f(x)+12=0
Option: 13 x^{2}+2 x f(x)+4=0
Option: 14 x^{2}+2 x f(x)+4=0
Option: 15 x^{2}+2 x f(x)+4=0
Option: 16 x^{2}+2 x f(x)+4=0

Answers (1)

best_answer

Let\, y= f\left ( x \right )
x\frac{dy}{dx}+y= x^{2}
\Rightarrow \frac{dy}{dx}+\frac{1}{x}\cdot y= x
Integrating\, Factor\: IF= e^{\int \frac{1}{x}}dx= e^{lnx}= x
\Rightarrow y\cdot x= \int x^{2}dx= \frac{x^{3}}{3}+C
Passes through (-2,2)
\Rightarrow 2\cdot \left ( -2 \right )= \frac{\left ( -2 \right )^{3}}{3}+C\Rightarrow C= \frac{8}{3}-4= \frac{-4}{3}
\Rightarrow y= \frac{x^{2}}{3}-\frac{4}{3x}= f\left ( x \right )
\Rightarrow x^{3}-3xf\left ( x \right )-4= 0
option (2)

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Kuldeep Maurya

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