Qus : 1
NIMCET PYQ
3
The coefficient of $x^{50}$ in the expression of ${(1 + x)^{1000} + 2x(1 + x)^{999} + 3x^2(1 + x)^{998} + ...... + 1001x^{1000}}$
1
$${}^{1005}{{C}}_{50}$$ 2
$${}^{1005}{{C}}_{48}$$ 3
$${}^{1002}{{C}}_{50}$$ 4
$${}^{1002}{{C}}_{51}$$ Go to Discussion
NIMCET Previous Year PYQ
NIMCET NIMCET 2023 PYQ
Solution
Easiest Method — Coefficient of \( x^{50} \)
Given Expression:
\[
(1 + x)^{1000} + 2x(1 + x)^{999} + 3x^2(1 + x)^{998} + \cdots + 1001x^{1000}
\]
This follows a known identity that simplifies the full expression to:
\[
f(x) = (1 + x)^{1002}
\]
Now: The coefficient of \( x^{50} \) in \( f(x) \) is:
\[
\boxed{\binom{1002}{50}}
\]
✅ Final Answer:
\( \boxed{\binom{1002}{50}} \)
Qus : 3
NIMCET PYQ
3
If
$(1 + x - 2x^2)^6 = 1 + a_1 x + a_2 x^2 + \ldots + a_{12} x^{12}$,
then the value of $a_2 + a_4 + a_6 + \ldots + a_{12}$ is:
1
1024
2
64 3
32 4
31 Go to Discussion
NIMCET Previous Year PYQ
NIMCET NIMCET 2009 PYQ
Solution Even–power coefficient sum = $\dfrac{f(1) + f(-1)}{2}$
$f(1) = (1 + 1 - 2)^6 = 0^6 = 0$
$f(-1) = (1 - 1 - 2)^6 = (-2)^6 = 64$
Required sum $= \dfrac{0 + 64}{2} = 32$
Qus : 4
NIMCET PYQ
3
The sum
$^{20}C_8 + ^{20}C_9 + ^{21}C_{10} + ^{22}C_{11} - ^{23}C_{11}$
1
$^{22}C_{12}$ 2
$^{23}C_{12}$ 3
$^{21}C_{10}$ 4
0 Go to Discussion
NIMCET Previous Year PYQ
NIMCET NIMCET 2012 PYQ
Solution Use Pascal identity:
$^{n}C_r + ^{n}C_{r+1} = ^{n+1}C_{r+1}$
So,
$^{20}C_8 + ^{20}C_9 = ^{21}C_9$
Then,
$^{21}C_9 + ^{21}C_{10} = ^{22}C_{10}$
Next,
$^{22}C_{10} + ^{22}C_{11} = ^{23}C_{11}$
Thus the expression becomes:
$^{23}C_{11} - ^{23}C_{11} = 0$
$\therefore$ the answer is 0.
Qus : 8
NIMCET PYQ
1
In the expression
$(x+1)(x+4)(x+9)(x+16)\cdots(x+400)$
the coefficient of $x^{19}$ is
1
$2870$ 2
$210$ 3
$4001$ 4
$1900$ Go to Discussion
NIMCET Previous Year PYQ
NIMCET NIMCET 2008 PYQ
Solution Coefficient of $x^{19}$ equals sum of constants:
$1+4+9+\cdots+400$
This is sum of squares from $1^2$ to $20^2$:
$\frac{20(21)(41)}{6}=2870$
Answer: $\boxed{2870}$
Qus : 9
NIMCET PYQ
2
If $(1+x)^n = a_0 + a_1 x + a_2 x^2 + \dots + a_n x^n$, then
$\left(1+\frac{a_1}{a_0}\right)\left(1+\frac{a_2}{a_1}\right)\left(1+\frac{a_3}{a_2}\right)\dots\left(1+\frac{a_n}{a_{n-1}}\right)$
1
$n^n/n!$ 2
$(n+1)^n/n!$ 3
$n^{n+1}/(n+1)!$ 4
$(n-1)^n/n!$ Go to Discussion
NIMCET Previous Year PYQ
NIMCET NIMCET 2010 PYQ
Solution Using $a_k = \binom{n}{k}$:
$1 + \frac{a_k}{a_{k-1}} = \frac{n+1}{k}$
Product = $\frac{(n+1)^n}{n!}$
Qus : 12
NIMCET PYQ
1
The coefficient of $x^{10}$ in the expansion of $\left(x^2+\frac{1}{x}\right)^{12}+\left(x+\frac{1}{x^2}\right)^{12}$ is:
1
0 2
12 3
66 4
112 Go to Discussion
NIMCET Previous Year PYQ
NIMCET NIMCET 2026 PYQ
Solution First expression is:
$\left(x^2+\frac{1}{x}\right)^{12}$
Its general term is:
$T_{k+1}={}^{12}C_k(x^2)^{12-k}\left(\frac{1}{x}\right)^k$
$T_{k+1}={}^{12}C_k x^{24-2k-k}$
$T_{k+1}={}^{12}C_k x^{24-3k}$
For coefficient of $x^{10}$,
$24-3k=10$
$3k=14$
$k=\frac{14}{3}$
This is not an integer, so $x^{10}$ term is not present in the first expression.
Now second expression is:
$\left(x+\frac{1}{x^2}\right)^{12}$
Its general term is:
$T_{k+1}={}^{12}C_k(x)^{12-k}\left(\frac{1}{x^2}\right)^k$
$T_{k+1}={}^{12}C_k x^{12-k-2k}$
$T_{k+1}={}^{12}C_k x^{12-3k}$
For coefficient of $x^{10}$,
$12-3k=10$
$3k=2$
$k=\frac{2}{3}$
This is also not an integer, so $x^{10}$ term is not present in the second expression.
Therefore, the coefficient of $x^{10}$ is $0$.
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