Qus : 2
Phrases PYQ
1
$\lim _{{x}\rightarrow1}\frac{{x}^4-1}{x-1}=\lim _{{x}\rightarrow k}\frac{{x}^3-{k}^2}{{x}^2-{k}^2}=$, then find k
1
8/3 2
4/3 3
2/3 4
1 Go to Discussion
Phrases Previous Year PYQ
Phrases NIMCET 2023 PYQ
Solution
Quick DL Method Solution
Given:
\[
\lim_{x \to 1} \frac{x^4 - 1}{x - 1}
= \lim_{x \to k} \frac{x^3 - k^2}{x^2 - k^2}
\]
LHS using derivative:
\[
\lim_{x \to 1} \frac{x^4 - 1}{x - 1} = \left.\frac{d}{dx}(x^4)\right|_{x=1} = 4x^3|_{x=1} = 4
\]
RHS using DL logic:
\[
\lim_{x \to k} \frac{x^3 - k^2}{x^2 - k^2}
\approx \frac{3k^2(x - k)}{2k(x - k)} = \frac{3k}{2}
\]
Equating both sides:
\[
\frac{3k}{2} = 4 \Rightarrow k = \frac{8}{3}
\]
\[
\boxed{k = \frac{8}{3}}
\]
Qus : 4
Phrases PYQ
3
The value of
$\displaystyle \lim_{n\to\infty} \frac{\pi}{n}\left[\sin\frac{\pi}{n}+\sin\frac{2\pi}{n}+\cdots+\sin\frac{(n-1)\pi}{n}\right]$
is:
1
0 2
$\pi$ 3
2 4
$\dfrac{\pi}{2}$ Go to Discussion
Phrases Previous Year PYQ
Phrases NIMCET 2012 PYQ
Solution This is a Riemann sum.
Rewrite the expression:
$\displaystyle \frac{\pi}{n}\sum_{k=1}^{n-1}\sin\left(\frac{k\pi}{n}\right)$
Let
$x_k = \frac{k\pi}{n}$
Then spacing
$\Delta x = \frac{\pi}{n}$
As $n\to\infty$, this becomes:
$\displaystyle \int_{0}^{\pi} \sin x , dx$
Now evaluate:
$\displaystyle \int_{0}^{\pi} \sin x dx = [-\cos x]_{0}^{\pi}$
$= (-\cos\pi) - (-\cos 0)$
$= -(-1) - (-1)$
$= 1 + 1 = 2$
$\therefore$ the value of the limit is 2.
Qus : 5
Phrases PYQ
1
$ \displaystyle \lim_{x\to 0} \frac{x+\sin x}{\sqrt{x}-\cos x} $
1
$0$ 2
$1$ 3
$-1$ 4
none of these Go to Discussion
Phrases Previous Year PYQ
Phrases NIMCET 2011 PYQ
Solution Use expansions:
$\sin x = x - \frac{x^{3}}{6} + \cdots$
$\cos x = 1 - \frac{x^{2}}{2} + \cdots$
$\sqrt{x}$ near $0$ goes to $0$
Numerator:
$ x + (x - \frac{x^{3}}{6}) = 2x + O(x^{3}) $
Denominator:
$ \sqrt{x} - \cos x = \sqrt{x} - 1 + \frac{x^{2}}{2} + \cdots $
As $x\to 0$, denominator → $-1$
So limit = $0$.
Qus : 6
Phrases PYQ
4
$\lim_{x\to3} \dfrac{\sqrt{3x}-3}{\sqrt{2x-4}-\sqrt{2}}$ is equal to
1
$\sqrt{3}$ 2
$\frac{\sqrt{3}}{2}$ 3
$\frac{1}{2\sqrt{2}}$ 4
$\frac{1}{\sqrt{2}}$ Go to Discussion
Phrases Previous Year PYQ
Phrases NIMCET 2019 PYQ
Solution
Rationalize numerator and denominator:
\[
\frac{\sqrt{3x}-3}{\sqrt{2x-4}-\sqrt{2}}
=\frac{\dfrac{3(x-3)}{\sqrt{3x}+3}}{\dfrac{2(x-3)}{\sqrt{2x-4}+\sqrt{2}}}
=\frac{3}{\sqrt{3x}+3}\cdot\frac{\sqrt{2x-4}+\sqrt{2}}{2}.
\]
Now let \(x\to 3\): \(\sqrt{3x}\to 3\) and \(\sqrt{2x-4}\to \sqrt{2}\). Hence
\[
\lim_{x\to 3}=\frac{3}{3+3}\cdot\frac{\sqrt{2}+\sqrt{2}}{2}
=\frac{1}{2}\cdot\sqrt{2}=\boxed{\frac{1}{2\sqrt{2}}}.
\]
Qus : 7
Phrases PYQ
4
The value of the limit $$\lim _{{x}\rightarrow0}\Bigg{(}\frac{{1}^x+{2}^x+{3}^x+{4}^x}{4}{\Bigg{)}}^{1/x}$$ is
1
1 2
$${3!}^{1/3!}$$ 3
$${3!}^{1/4}$$ 4
$${4!}^{1/4}$$ Go to Discussion
Phrases Previous Year PYQ
Phrases NIMCET 2024 PYQ
Solution We need to find:
$\displaystyle \lim_{x\to 0}\left( \frac{1^x + 2^x + 3^x + 4^x}{4} \right)^{1/x}$
Rewrite each term:
$k^x = e^{x\ln k}$
So:
$1^x + 2^x + 3^x + 4^x
= e^{0} + e^{x\ln 2} + e^{x\ln 3} + e^{x\ln 4}$
As $x \to 0$ use expansion:
$e^{x\ln k} = 1 + x\ln k + O(x^2)$
So:
$1^x + 2^x + 3^x + 4^x$
$= 1 + (1 + x\ln 2) + (1 + x\ln 3) + (1 + x\ln 4)$
$= 4 + x(\ln 2 + \ln 3 + \ln 4) + O(x^2)$
Thus:
$\frac{1^x + 2^x + 3^x + 4^x}{4}
= 1 + \frac{x(\ln 2 + \ln 3 + \ln 4)}{4} + O(x^2)$
Now apply the standard limit:
$\lim_{x\to 0} (1 + kx)^{1/x} = e^{k}$
Here:
$k = \frac{\ln 2 + \ln 3 + \ln 4}{4}$
Hence the limit is:
$e^{(\ln 2 + \ln 3 + \ln 4)/4}$
Combine logs:
$\ln 2 + \ln 3 + \ln 4 = \ln(2\cdot 3 \cdot 4) = \ln 24$
Final answer:
$\boxed{24^{1/4}}$
Qus : 11
Phrases PYQ
3
The value of ${{Lt}}_{x\rightarrow0}\frac{{e}^x-{e}^{-x}-2x}{1-\cos x}$ is equal to
1
2 2
1 3
0 4
-1 Go to Discussion
Phrases Previous Year PYQ
Phrases NIMCET 2024 PYQ
Solution
Evaluate:
$$\lim_{x \to 0} \frac{e^x - e^{-x} - 2x}{1 - \cos x}$$
Step 1: Apply L'Hôpital's Rule (since it's 0/0):
First derivative:
$$\frac{e^x + e^{-x} - 2}{\sin x}$$
Still 0/0 → Apply L'Hôpital's Rule again:
$$\frac{e^x - e^{-x}}{\cos x}$$
Now,
$$\lim_{x \to 0} \frac{1 - 1}{1} = 0$$
Final Answer:
$$\boxed{0}$$
Qus : 14
Phrases PYQ
1
Let f(x) be a polynomial of degree four, having extreme value at x = 1 and x = 2. If $\lim _{{x}\rightarrow0}[1+\frac{f(x)}{{x}^2}]=3$, then f(2) is
1
0 2
4 3
- 8 4
- 4 Go to Discussion
Phrases Previous Year PYQ
Phrases NIMCET 2017 PYQ
Solution Given it has extremum values at x=1 and x=2
⇒f′(1)=0 and f′(2)=0
Given f(x) is a fourth degree polynomial
Let $f(x)=a{x}^4+b{x}^3+c{x}^2+dx+e$
Given
$\lim _{{x}\rightarrow0}[1+\frac{f(x)}{{x}^2}]=3$
$\lim _{{x}\rightarrow0}\lbrack1+\frac{a{x}^4+b{x}^3+c{x}^2+\mathrm{d}x+e}{{x}^2}\rbrack=3$
$\lim _{{x}\rightarrow0}\lbrack1+a{x}^2+bx+c+\frac{d}{x}+\frac{e}{{x}^2}\rbrack=3$
For limit to have finite value, value of 'd' and 'e' must be 0
⇒d=0 & e=0
Substituting x=0 in limit
⇒ c+1=3
⇒ c=2
$f^{\prime}(x)=4a{x}^3+3b{x}^2+2cx+d$
$x=1$ and $x=2$ are extreme values,
⇒$f^{\prime}(1)=0$ and $f^{\prime}(2)=0
⇒ $4a+3b+4=0$ and $32a+12b+8=0$
By solving these equations
we get, $a=\frac{1}{2}$ and $b=-2$
So,
$f(x)=\frac{x^{4}}{2}-2x^{3}+2x^{2}$
⇒$f(x)=x^{2}(\frac{x^{2}}{2}-2x+2)$
⇒$f(2)=0$
Qus : 16
Phrases PYQ
1
What is the value of $\lim _{{x}\rightarrow\infty}-(x+1)\Bigg{(}{e}^{\frac{1}{x+1}}-1\Bigg{)}$?
1
-1 2
1 3
0 4
Does not exist Go to Discussion
Phrases Previous Year PYQ
Phrases NIMCET 2025 PYQ
Solution We want to evaluate
$ \displaystyle \lim_{x \to \infty} -(x+1)\left(e^{\frac{1}{x+1}} - 1\right). $
Rewrite it as a product:
$ -(x+1)\left(e^{\frac{1}{x+1}} - 1\right)
= -\dfrac{e^{\frac{1}{x+1}} - 1}{\frac{1}{x+1}}. $
Now let
$ t = \frac{1}{x+1} \Rightarrow t \to 0^+ $ as $ x \to \infty $.
The expression becomes:
$ -\dfrac{e^{t} - 1}{t}. $
Now apply L'Hospital’s Rule to the limit:
$ \displaystyle \lim_{t \to 0} \dfrac{e^{t} - 1}{t}
= \lim_{t \to 0} \dfrac{e^{t}}{1}
= 1. $
So the original limit is:
$ -1. $
Final Answer: $ -1 $.
Qus : 17
Phrases PYQ
4
$\lim_{x\to0} \dfrac{x \tan x}{(1-\cos x)}$
1
1/2 2
-1/2 3
- 2 4
2 Go to Discussion
Phrases Previous Year PYQ
Phrases NIMCET 2017 PYQ
Solution
Given limit is indeterminate of type $\frac{0}{0}$.
(DL Rule) Differentiate numerator and denominator:
$\displaystyle \lim_{x\to0}\frac{x\tan x}{1-\cos x}=\lim_{x\to0}\frac{\tan x+x\sec^2 x}{\sin x}$
As $x\to0$, $\tan x\approx x$, $\sin x\approx x$, $\sec^2 x\approx1$
$\Rightarrow \dfrac{x+x}{x}=2$
Answer: $\boxed{2}$ ✅
Qus : 18
Phrases PYQ
4
If
$A = \begin{bmatrix} \cos\alpha & \sin\alpha \\ -\sin\alpha & \cos\alpha \end{bmatrix},$
then for any positive integer $n$, $A^n$ is
1
$$
\begin{bmatrix} sinn \alpha & cosn \alpha \\ cosn \alpha & -sinn \alpha \end{bmatrix}
\quad
$$ 2
$$
\begin{bmatrix} cos n \alpha & sin n \alpha \\ sin n \alpha & cos n \alpha \end{bmatrix}
\quad
$$ 3
$$ \begin{bmatrix} cos nn \alpha & sinn \alpha \\ sinn \alpha & -cosn \alpha \end{bmatrix} \quad $$ 4
$$ \begin{bmatrix} cos nn \alpha & sinn \alpha \\ -sinn \alpha & cosn \alpha \end{bmatrix} \quad $$ Go to Discussion
Phrases Previous Year PYQ
Phrases NIMCET 2020 PYQ
Solution
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