MCQ
If ${e^y} + xy = e$, the ordered pair $\left( {\frac{{dy}}{{dx}},\frac{{{d^2}y}}{{d{x^2}}}} \right)$ at $x = 0$ is equal to
  • A
    $\left( {\frac{1}{e}, - \frac{1}{{{e^2}}}} \right)$
  • B
    $\left( {\frac{1}{e},  \frac{1}{{{e^2}}}} \right)$
  • $\left( { - \frac{1}{e},\frac{1}{{{e^2}}}} \right)$
  • D
    $\left( { - \frac{1}{e}, - \frac{1}{{{e^2}}}} \right)$

Answer

Correct option: C.
$\left( { - \frac{1}{e},\frac{1}{{{e^2}}}} \right)$
c
${e^y} = xy = e$ differentiate w.r.t. $x$

${e^y}\frac{{dy}}{{dx}} + x\frac{{dy}}{{dx}} + y = 0$

${e^y}\frac{{dy}}{{dx}} + x\frac{{dy}}{{dx}} + y = 0$

$\frac{{dy}}{{dx}}\left( {x + {e^y}} \right) =  - y,{\left. {\frac{{dy}}{{dx}}} \right|_{\left( {0,1} \right)}} =  - \frac{1}{e}$ again differentate w.r.t. $x$

${e^y}.\frac{{{d^2}y}}{{d{x^2}}} + \frac{{dy}}{{dx}}.{e^y}.\frac{{dy}}{{dx}} + x.\frac{{{d^2}y}}{{d{x^2}}} + \frac{{dy}}{{dx}} + \frac{{dy}}{{dx}} = 0$

$\left( {x + {e^y}} \right)\frac{{{d^2}y}}{{d{x^2}}} + {\left( {\frac{{dy}}{{dx}}} \right)^2}.{e^y} + 2\frac{{dy}}{{dx}} = 0$

$e\frac{{{d^2}y}}{{d{x^2}}} + \frac{1}{{{e^1}}}e + 2\left( { - \frac{1}{e}} \right) = 0$

$\therefore \frac{{{d^2}y}}{{d{x^2}}} + \frac{1}{{{e^2}}}$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

Unboundedness is usually a sign that the $\text{LP}$ problem.
If a line makes an angle of $\frac{\pi }{4}$ with the positive directions of each of $x- $ axis and $y-$ axis, then the angle that the line makes with the positive direction ofthe $z-$ axis is
$\int\limits^{\frac{\pi}{2}}_0\sin2\text{x }\log\tan\text{x dx}$ is equal to:
Let $f$ be an injective map with domain $\{x, y, z\}$ and range $\{1, 2, 3\}$, such that exactly one of the following statements is correct and the remaining are false. $\text{f(x)}=1,\ \text{f(y)}\neq1,\ \text{f(z)}\neq2.$The value of $f ^{-1}(1)$ is
The probability that a leap year will have $53$ sundays is:
Choose the correct answer from the given four option.The integrating factor of the differential equation $\frac{\text{d}\text{y}}{\text{d}\text{x}}+\text{y}=\frac{1+\text{y}}{\text{x}}$ is:
$\int\frac{1}{1-\cos\text{x}-\sin\text{x}}\text{ dx}=$
For $a>0,$ let the curves $C_{1}: y^{2}=a x$ and $\mathrm{C}_{2}: \mathrm{x}^{2}=$ ay intersect at origin $\mathrm{O}$ and a point $\mathrm{P}$ Let the line $\mathrm{x}=\mathrm{b}(0<\mathrm{b}<\mathrm{a})$ intersect the chord $OP$ and the $\mathrm{x}$ -axis at points $\mathrm{Q}$ and $\mathrm{R}$, respectively. If the line $x=b$ bisects the area bounded by the curves, $\mathrm{C}_{1}$ and $\mathrm{C}_{2},$ and the area of $\Delta \mathrm{OQR}=\frac{1}{2},$ then '$a$' satisfies the equation
$\frac{d}{{dx}}\left( {{e^{\sqrt {1 - {x^2}} }}.\tan x} \right)$
The maximum value of $\sin x\,\,(1 + \cos x)$ will be at the