(B): Equation of ellipses \(\frac{\mathrm{x}^{2}}{\mathrm{a}^{2}}+\frac{\mathrm{y}^{2}}{\mathrm{~b}^{2}}=1\) Differentiate both side w.r.t. \(\mathrm{x}\), \(\frac{2 x}{a^{2}}+\frac{2 y}{b^{2}} \frac{d y}{d x}=0\) \(\frac{2 y}{b^{2}} \frac{d y}{d x}=-\frac{2 x}{a^{2}}\) \(\frac{y}{x} \frac{d y}{d x}=-\frac{b^{2}}{a^{2}}\) Again differentiating both side w.r.t. \(x\), \(\frac{y}{x} \frac{d}{d x}\left(\frac{d y}{d x}\right)+y^{\prime} \frac{d}{d x}\left(\frac{x}{y}\right)=0\) \(\frac{y}{x} y^{\prime \prime}+y^{\prime}\left(\frac{x y^{\prime}-y \times 1}{x^{2}}\right)=0\) \(\frac{y}{x} y^{\prime \prime}+y^{\prime}\left(\frac{x y^{\prime}-y}{x^{2}}\right)=0\) \(x^{\prime \prime}+x y^{\prime 2}-y^{\prime}=0\)
WB JEE-2021
Differential Equation
87646
The population \(P=P(t)\) at time \(t\) of a certain species follows the differential equation \(\frac{d p}{d t}=0.5 P-450\). If \(P(0)=850\), then the time at which population becomes zero is
(B): Equation of ellipses \(\frac{\mathrm{x}^{2}}{\mathrm{a}^{2}}+\frac{\mathrm{y}^{2}}{\mathrm{~b}^{2}}=1\) Differentiate both side w.r.t. \(\mathrm{x}\), \(\frac{2 x}{a^{2}}+\frac{2 y}{b^{2}} \frac{d y}{d x}=0\) \(\frac{2 y}{b^{2}} \frac{d y}{d x}=-\frac{2 x}{a^{2}}\) \(\frac{y}{x} \frac{d y}{d x}=-\frac{b^{2}}{a^{2}}\) Again differentiating both side w.r.t. \(x\), \(\frac{y}{x} \frac{d}{d x}\left(\frac{d y}{d x}\right)+y^{\prime} \frac{d}{d x}\left(\frac{x}{y}\right)=0\) \(\frac{y}{x} y^{\prime \prime}+y^{\prime}\left(\frac{x y^{\prime}-y \times 1}{x^{2}}\right)=0\) \(\frac{y}{x} y^{\prime \prime}+y^{\prime}\left(\frac{x y^{\prime}-y}{x^{2}}\right)=0\) \(x^{\prime \prime}+x y^{\prime 2}-y^{\prime}=0\)
WB JEE-2021
Differential Equation
87646
The population \(P=P(t)\) at time \(t\) of a certain species follows the differential equation \(\frac{d p}{d t}=0.5 P-450\). If \(P(0)=850\), then the time at which population becomes zero is
(B): Equation of ellipses \(\frac{\mathrm{x}^{2}}{\mathrm{a}^{2}}+\frac{\mathrm{y}^{2}}{\mathrm{~b}^{2}}=1\) Differentiate both side w.r.t. \(\mathrm{x}\), \(\frac{2 x}{a^{2}}+\frac{2 y}{b^{2}} \frac{d y}{d x}=0\) \(\frac{2 y}{b^{2}} \frac{d y}{d x}=-\frac{2 x}{a^{2}}\) \(\frac{y}{x} \frac{d y}{d x}=-\frac{b^{2}}{a^{2}}\) Again differentiating both side w.r.t. \(x\), \(\frac{y}{x} \frac{d}{d x}\left(\frac{d y}{d x}\right)+y^{\prime} \frac{d}{d x}\left(\frac{x}{y}\right)=0\) \(\frac{y}{x} y^{\prime \prime}+y^{\prime}\left(\frac{x y^{\prime}-y \times 1}{x^{2}}\right)=0\) \(\frac{y}{x} y^{\prime \prime}+y^{\prime}\left(\frac{x y^{\prime}-y}{x^{2}}\right)=0\) \(x^{\prime \prime}+x y^{\prime 2}-y^{\prime}=0\)
WB JEE-2021
Differential Equation
87646
The population \(P=P(t)\) at time \(t\) of a certain species follows the differential equation \(\frac{d p}{d t}=0.5 P-450\). If \(P(0)=850\), then the time at which population becomes zero is
(B): Equation of ellipses \(\frac{\mathrm{x}^{2}}{\mathrm{a}^{2}}+\frac{\mathrm{y}^{2}}{\mathrm{~b}^{2}}=1\) Differentiate both side w.r.t. \(\mathrm{x}\), \(\frac{2 x}{a^{2}}+\frac{2 y}{b^{2}} \frac{d y}{d x}=0\) \(\frac{2 y}{b^{2}} \frac{d y}{d x}=-\frac{2 x}{a^{2}}\) \(\frac{y}{x} \frac{d y}{d x}=-\frac{b^{2}}{a^{2}}\) Again differentiating both side w.r.t. \(x\), \(\frac{y}{x} \frac{d}{d x}\left(\frac{d y}{d x}\right)+y^{\prime} \frac{d}{d x}\left(\frac{x}{y}\right)=0\) \(\frac{y}{x} y^{\prime \prime}+y^{\prime}\left(\frac{x y^{\prime}-y \times 1}{x^{2}}\right)=0\) \(\frac{y}{x} y^{\prime \prime}+y^{\prime}\left(\frac{x y^{\prime}-y}{x^{2}}\right)=0\) \(x^{\prime \prime}+x y^{\prime 2}-y^{\prime}=0\)
WB JEE-2021
Differential Equation
87646
The population \(P=P(t)\) at time \(t\) of a certain species follows the differential equation \(\frac{d p}{d t}=0.5 P-450\). If \(P(0)=850\), then the time at which population becomes zero is
(B): Equation of ellipses \(\frac{\mathrm{x}^{2}}{\mathrm{a}^{2}}+\frac{\mathrm{y}^{2}}{\mathrm{~b}^{2}}=1\) Differentiate both side w.r.t. \(\mathrm{x}\), \(\frac{2 x}{a^{2}}+\frac{2 y}{b^{2}} \frac{d y}{d x}=0\) \(\frac{2 y}{b^{2}} \frac{d y}{d x}=-\frac{2 x}{a^{2}}\) \(\frac{y}{x} \frac{d y}{d x}=-\frac{b^{2}}{a^{2}}\) Again differentiating both side w.r.t. \(x\), \(\frac{y}{x} \frac{d}{d x}\left(\frac{d y}{d x}\right)+y^{\prime} \frac{d}{d x}\left(\frac{x}{y}\right)=0\) \(\frac{y}{x} y^{\prime \prime}+y^{\prime}\left(\frac{x y^{\prime}-y \times 1}{x^{2}}\right)=0\) \(\frac{y}{x} y^{\prime \prime}+y^{\prime}\left(\frac{x y^{\prime}-y}{x^{2}}\right)=0\) \(x^{\prime \prime}+x y^{\prime 2}-y^{\prime}=0\)
WB JEE-2021
Differential Equation
87646
The population \(P=P(t)\) at time \(t\) of a certain species follows the differential equation \(\frac{d p}{d t}=0.5 P-450\). If \(P(0)=850\), then the time at which population becomes zero is