MCQ
If ${x^x}{y^y}{z^z} = c$, then ${{\partial z} \over {\partial x}} = $
  • A
    ${{1 + \log x} \over {1 + \log z}}$
  • $ - {{1 + \log x} \over {1 + \log z}}$
  • C
    $ - {{1 + \log y} \over {1 + \log z}}$
  • D
    None of these

Answer

Correct option: B.
$ - {{1 + \log x} \over {1 + \log z}}$
b
(b) ${x^x}{y^y}{z^z} = c$ ==> $\log ({x^x}{y^y}{z^z}) = \log c$

==> $x\log x + y\log y + z\log z = \log c$ .....$(i)$

Here $x, y$ are regarded as independent variables and $z $ depends on  $x, y.$

Differentiating $ (i) $ partially  $w.r.t. ‘x’$

$x.\frac{1}{x} + \log x.1 + 0 + \left( {z.\frac{1}{z} + \log z.1} \right)\frac{{\partial z}}{{\partial x}} = 0$

$\therefore $ $\frac{{\partial z}}{{\partial x}} = - \frac{{1 + \log x}}{{1 + \log z}}$.

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

Choose the correct answer from the given four options.$\text{P}\Big(\frac{\text{B}}{\text{A}}\Big)$ is equal to:
If $a + b + c = 50$ and $a$, $b$, $c$ are non negative even integers, then greatest value of $ab^2c$ is 
Let a, b, c be positive real numbers. The following system of equations in x, y and z $\frac{\text{x}^2}{\text{a}^2}+\frac{\text{y}^2}{\text{b}^2}-\frac{\text{z}^2}{\text{c}^2}=1,$ $\frac{\text{x}^2}{\text{a}^2}-\frac{\text{y}^2}{\text{b}^2}+\frac{\text{z}^2}{\text{c}^2}=1,$ $-\frac{\text{x}^2}{\text{a}^2}+\frac{\text{y}^2}{\text{b}^2}+\frac{\text{z}^2}{\text{c}^2}=1$ has:
Choose the correct answer from the given four options:
Maximum slope of the curve $y = -x^3 + 3x^2 + 9x - 27$ is:
The given table shows the number of cars manufactured in four different colours on a particular day. Study it carefully and answer the question.
 
Number of cars manufactured
Colour
Vento
Creta
Wagonr
Red
$65$ $88$ $93$
White
$54$ $42$ $80$
Black
$66$ $52$ $88$
Sliver
$37$ $49$ $74$
Which car was twice the number of silver Vento?
$\int_0^{\pi /3} {\cos 3x\,dx = } $
A unit vector perpendicular to the plane containing the vectors $i - j + k$ and $ - i + j + k$ is
If $A$ is a $3\times3$ matrix such that $\left| {5.adjA} \right| = 5$, then $\left| A \right|$ is equal to
Integrating factor of the differential equation, $(1-\text{x}^2)\frac{\text{dy}}{\text{dx}}-\text{xy}=1$ is:
If ${\sin ^{ - 1}}x + {\cot ^{ - 1}}\left( {\frac{1}{2}} \right) = \frac{\pi }{2},$ then  $x $ is