user avatar
user avatar
user avatar
User
  • Member for 4 months
  • Last seen this week
6 votes
4 answers
278 views

Is everything ok with this notation? $A=\{x\mid 2x,x\in\Bbb{N}\}$

5 votes
2 answers
132 views

How can I prove that, if $x,y,z>0$ and $xyz=1$, then $2(x^2+y^2+z^2)+9\geq 5(x+y+z)$

4 votes
1 answer
87 views

A functional calculus question

3 votes
2 answers
129 views

Showing $\frac{xy+yz+xz}{x+y+z}>5-\sqrt{4(x^2+y^2+z^2)+6}$ for $x,y,z>0$ and $xyz=1$

2 votes
3 answers
89 views

Prove that $(xy+yz+xz)(x^2+y^2+z^2+x+y+z)≥2(x+y+z)^2$

2 votes
2 answers
59 views

Can we prove the inequality without opening the parentheses? $(x+y+z)(xy+yz+xz)(x^2+y^2+z^2)≥6(x^2+y^2+z^2)+3(xy+yz+xz)$

2 votes
1 answer
72 views

Proving $\frac{x^2+y^2+z^2}{x+y+z}+\frac 32\sqrt[3]\frac{xy+yz+xz}{x+y+z}\geq \frac 52$, for positive values with $xyz=1$, without expansion?

2 votes
1 answer
64 views

Is there a solution for $(\frac{3}{x+y+z})^n+(\frac{3}{x+y+z})^{5-n}<2$?

2 votes
1 answer
62 views

What is the value of $a_1a_2\cdots a_{2019}$?

2 votes
1 answer
61 views

An unusual inequality problem involving real exponential power

2 votes
2 answers
110 views

Find the degree of the $P(x)$

1 vote
0 answers
88 views

Can we call the graph of the function $f:\mathbb [-2,3]\rightarrow \mathbb R,\,\,\, f(x)=x^2+3x+5$ "Parabola"?

1 vote
2 answers
113 views

Is this nice-looking inequality actually trivial?

0 votes
1 answer
117 views

Constructing the set $D$ that satisfies the equation $f(x)=x+1$

0 votes
1 answer
95 views

A factorization of $x^7+x^3+x-1=0$ over rationals