MCQ
If $x=t^2+1, y=2 a t$, then $\frac{d^2 y}{d x^2}$ at $t=a$ is
  • A
    $-\frac{1}{a}$
  • B
    $-\frac{1}{2 a^2}$
  • C
    $\frac{1}{2 \sigma^2}$
  • D
    $0$

Answer

Given, $x=t^2+1$ and $y=2 a t$
\[
\begin{array}{l}
\Rightarrow \frac{d x}{d t}=2 t \Rightarrow \frac{d y}{d t}=2 a \therefore \frac{d y}{d x}=\frac{a}{t} \\
\Rightarrow \frac{d^2 y}{d x^2}=\frac{-a}{t^2} \cdot \frac{d t}{d x}=\frac{-a}{2 t^3} \therefore\left(\frac{d^2 y}{d x^2}\right)_{a t t=a}=\frac{-a}{2 a^3}=\frac{-1}{2 a^2}
\end{array}
\]

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

The area bounded by the parabola $x^2=4 y$ and its latus rectum is:
The locus of  a point equidistant from two given points $ a$  and $ b $ is given by
A unit vector perpendicular to both $\hat{\text{i}}+\hat{\text{j}}$ and $\hat{\text{j}}+\hat{\text{k}}$ is:
  1. $\hat{\text{i}}-\hat{\text{j}}+\hat{\text{k}}$
  2. $\hat{\text{i}}+\hat{\text{j}}+\hat{\text{k}}$
  3. $\frac{1}{\sqrt{3}}\big(\hat{\text{i}}+\hat{\text{j}}+\hat{\text{k}}\big)$
  4. $\frac{1}{\sqrt{3}}\big(\hat{\text{i}}-\hat{\text{j}}+\hat{\text{k}}\big)$
$\int {{e^{{x^2}}}}  \cdot {e^x}\left( {2{x^2} + x + 1} \right)dx = {e^{{x^2}}}\left( {f\left( x \right)} \right) + c$ where $c$ is constant of integration. If the minimum value of $f(x) $ is equal to $'m'$ then find the value of $\left[ { - \frac{1}{m}} \right]$ , $[·]$ denotes $[GIF]$ functions
Choose the correct answer from the given four options.

The value of the expression $\tan\Big(\frac{1}{2}\cos^{-1}\frac{2}{\sqrt{5}}\Big)$ is:

  1. $2+\sqrt{5}$

  2. $\sqrt{5}-2$

  3. $\frac{\sqrt{5}+2}{2}$

  4. $5+\sqrt{2}$

Hint: $\bigg[\tan\frac{\theta}{2}=\sqrt{\frac{1-\cos\theta}{1+\cos\theta}}\bigg]$

Let $A = \left( {\begin{array}{*{20}{c}}0&0&{ - 1}\\0&{ - 1}&0\\{ - 1}&0&0\end{array}} \right)$, the only correct statement about the matrix $A$ is
For the differential equation, general solution for $x\,\cos \left( {\frac{y}{x}} \right)\left( {ydx + xdy} \right) = y\,\sin \left( {\frac{y}{x}} \right)\left( {xdy - ydx} \right)$ , (where $c$ is constant of integration) is
The lines $x = ay + b,\;z = cy + d$ and $x = a'y + b',\;z = c'y + d'$ are perpendicular to each other, if
$\lim _{n \rightarrow \infty}\left[\frac{1}{n}+\frac{n}{(n+1)^{2}}+\frac{n}{(n+2)^{2}}+\ldots \ldots .+\frac{n}{(2 n-1)^{2}}\right]$ is equal to ...... .
If $I = \int_0^{100\pi } {\sqrt {(1 - \cos 2x)} \,dx,} $ then the value of $I$ is