Find the coefficient of $x^9$ in the expansion of $(1+x)(1+x^2)(1+x^3)...(1+x^{100})$
110955
Find the coefficient of $x^9$ in $(1+x)(1+x^2)(1+x^3)\cdots(1+x^{100})$
49028
Find the sum : $\frac{1}{\cos0^\circ\cos1^\circ}+\frac{1}{\cos1^\circ \cos2^\circ} +\frac{1}{\cos2^\circ \cos3^\circ}+......+$
32122
Find the coefficient of the term $x^2$ in $\left(x+\frac 2x\right)^{4}$
117099
Coefficient Problem (polynomial expansion)
112147
Proving $9$ divides $n^3 + (n+1)^3 + (n+2)^3$
110869
Find the coefficient of $z$ in the Laurent series expansion of $\frac{e^z}{z-1}$ in ${|z| > 1}$
33992
Let $\theta$ be a root of $p(x)=x^3+9x+6$, find the inverse of $1+\theta$ in $\mathbb{Q(\theta)}$
60122
Prove $(1+a+b)(1+b+c)(1+c+a)\ge 9(ab+bc+ca)$
49744
Find remainder of division of $x^3$ by $x^2-x+1$
118411
Computing the coefficient in a large polynomial
9490
Let $(1+x+x^2)^n=a_0+a_1x+a_2x^2+\cdots+a_{2n}x^{2n}$ be an identity in $x$. Find $a_0 +a_2 +a_4+ \cdots +a_{2n} $ in terms of $n$
23638
$a^2b^2+a^2c^2+b^2c^2\leq 3$
146753
Find $x$ such that $(x^2 + 4x + 3)^x + (2x + 4)^x = (x^2 + 4x + 5)^x$
101019
$x^3-9=y^2$ find integral solutions
81596
Series expansion at $x=0$ of $\frac{3x}{1+x^2 + x^4}$
132169
$x^{2000} + \frac{1}{x^{2000}}$ in terms of $x + \frac 1x$.
134311
How to determine equation for $\sum_{k=1}^n k^3$