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

A line passes through the points $(6, −7, −1)$ and $(2, −3, 1).$ The direction cosines of the line so directed that the angle made by it with the positive direction of $x-$ axis is acute, is?
If the determinant $\begin{vmatrix}\text{a}&\text{b}&2\text{a}\alpha+3\text{b}\\\text{b}&\text{c}&2\text{b}\alpha+3\text{c}\\2\text{a}\alpha+ 3\text{b}&2\text{b}\alpha+3\text{c}&0\end{vmatrix}=0,$ then :
Let $\alpha, \beta, \gamma$ be the real roots of the equation, $x ^{3}+ ax ^{2}+ bx + c =0,( a , b , c \in R$ and $a , b \neq 0)$ If the system of equations (in, $u,v,w$) given by $\alpha u+\beta v+\gamma w=0, \beta u+\gamma v+\alpha w=0$ $\gamma u +\alpha v +\beta w =0$ has non-trivial solution, then the value of $\frac{a^{2}}{b}$ is
Directions: In the following questions, the Assertions $(A)$ and Reason$(s)\ (R)$ have been put forward. Read both the statements carefully and choose the correct alternative from the following:
Assertion $(A) \frac{\text{d}}{\text{dx}}(\text{x}^2+\text{x}+1)^4=(\text{x}^2+\text{x}+1)^3(2\text{x}+1)$
Reason $(R) (\text{fog}'=\text{f'}[\text{g(x)}].\text{g'(x)}$
If $P$ is a point on the parabola $y=x^{2}+4$ which is closest to the straight line $y =4 x -1,$ then the co-ordinates of $P$ are :
$\int_{}^{} {{{\cos }^5}x\;dx = } $
Let $A=\left[\begin{array}{cc}i & -i \\ -i & i\end{array}\right], i=\sqrt{-1}$.Then, the system of linear equations $A^{8}\left[\begin{array}{l}x \\ y\end{array}\right]=\left[\begin{array}{c}8 \\ 64\end{array}\right]$ has :
For linear programming $x+2 y \geq 10,3 x+4 y \leq 24$ and $x \geq 0, y \geq 0 \ldots \ldots \ldots .$ is not the corner point of feasible region.
Find the absolute maximum value of $f(x)=4 x-\frac{1}{2} x^2$ in interval $\left[-2, \frac{9}{2}\right]$.
Let $A$ is a symmetric and $ \,B$ is a skew symmetric matrix, such that  $A - B = \left[ {\begin{array}{*{20}{c}}
  1&2 \\ 
  3&4 
\end{array}} \right]$, then $|A|$ is