Why doesn't $(x+y)^2 $equal $x^2+y^2$?
122920
Why is $y + x = 3$ not the same as $y^2 + x^2 = 9$
102306
Why is this simple calculation of two doubles inaccurate?
100913
It is impossible for $(x-1)^2+x^2+(x+1)^2$ to be a perfect square
86567
Understanding $\sum_{x = 0}^y x = \frac{y(y + 1)}{2}$ in a step of a proof
58212
Why doesn't the quadratic equation contain $2|a|$ in the denominator?
82630
How is it, that $\sqrt{x^2}$ is not $ x$, but $|x|$?
41300
Show $(x+y)^a > x^a + y^a$ for $x,y>0$ and $a>1$
31317
If we know $x+y+z=1$, $x^2+y^2+z^2=2$, and $x^3+y^3+z^3=3$, how to find $x^4+y^4+z^4$?
69172
$y'=$ ${-x+\sqrt{(x^2+4y)}}\over 2$ , $y(2)=-1$
20481
Volume enclosed by $(x^2+y^2+z^2)^2=x$
94700
Integer solutions for $x^3+2=y^2$?
87665
Proving $x^n - y^n = (x-y)(x^{n-1} + x^{n-2} y + ... + x y^{n-2} + y^{n-1})$
88760
Find the integral solutions to $ x^2+y^2+z^2=x^2y^2$
41364
How to prove that $x^y - y^x = x + y$ has only one solution in positive integers?
41204
Why do I get one extra wrong solution when solving $2-x=-\sqrt{x}$?
84315
Why can't polynomials have negative exponents or division by a variable
121658
$x^2+y^2-1$ irreducible in $\mathbb{Q}[x,y]$?