MCQ
Let y =$\sqrt {x\,\, + \,\,\sqrt {x\,\, + \,\,\sqrt {x\,\, + \,\,......\,\,\infty } } }$ then $\frac{{dy}}{{dx}}$ =
  • A
    $\frac{1}{{2\,y\,\, - \,\,1}}$
  • B
    $\frac{y}{{2x\,\, + \,\,y}}$
  • C
    $\frac{1}{{\sqrt {1\,\, + \,\,4x} }}$
  • All of the above

Answer

Correct option: D.
All of the above
d
$y^2 = x + y ==>\frac{{dy}}{{dx}} =$$\frac{1}{{2\,y\,\, - \,\,1}}$

also $y =\frac{x}{y} + 1 $

$==>\frac{{dy}}{{dx}} =\frac{y}{{2\,x\,\, + \,\,y}}$ 

make a quadratic in $y$ to get explicit function $==> C$ 

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

$\int_0^{2\pi } {\sqrt {1 + \sin \frac{x}{2}} \,dx = } $
Let $\vec{a}, \vec{b}$ and $\vec{c}$ be three units vectors such that $\overrightarrow{\mathrm{a}}+\overrightarrow{\mathrm{b}}+\overrightarrow{\mathrm{c}}=\overrightarrow{0} .$ If $\lambda=\overrightarrow{\mathrm{a}} \cdot \overrightarrow{\mathrm{b}}+\overrightarrow{\mathrm{b}} \cdot \overrightarrow{\mathrm{c}}+\overrightarrow{\mathrm{c}} \cdot \overrightarrow{\mathrm{a}} $ and $\overrightarrow{\mathrm{d}}=\overrightarrow{\mathrm{a}} \times \overrightarrow{\mathrm{b}}+\overrightarrow{\mathrm{b}} \times \overrightarrow{\mathrm{c}}+\overrightarrow{\mathrm{c}} \times \overrightarrow{\mathrm{a}},$ then the ordered pair $(\lambda, {\mathrm{\vec d}})$ is equal to 
The point $P(10,\;7)$ lies outside the circle ${x^2} + {y^2} - 4x - 2y - 20 = 0$. The greatest distance of $P$ from the circle is
The numbers of arrangements of the letters of the word $SALOON$, if the two $O's$ do not come together, is
The equation of the hyperbola whose foci are the foci of the ellipse $\frac{{{x^2}}}{{25}} + \frac{{{y^2}}}{9} = 1$ and the eccentricity is $2$, is
If $f\left( x \right) = {e^{{{\left( {x + 1} \right)}^n}}};\left( {n \in N} \right)$ then value of $'n'$ for which $f''\left( 1 \right) = 67\left( {{2^n}{e^{2n}}} \right)$ is
If $a = \cos (2\pi /7) + i\,\sin (2\pi /7),$ then the quadratic equation whose roots are $\alpha = a + {a^2} + {a^4}$ and $\beta = {a^3} + {a^5} + {a^6}$ is
$\left| {\,\begin{array}{*{20}{c}}{1 + x}&1&1\\1&{1 + y}&1\\1&1&{1 + z}\end{array}\,} \right| = $
If position vectors of a point $A$ is  $a + 2b$  and a divides  $ AB $ in the ratio $2:3$, then the position vector of $ B$  is
The radius of the circle whose arc of length $15\,cm$ makes an angle of $3/4$ radian at the centre is .....$cm$