Systems of Equations
\[\begin{cases} 4\dfrac{\sqrt{x^{2} + 1}}{x} = 5\dfrac{\sqrt{y^{2} + 1}}{y}=6\dfrac{\sqrt{z^{2} + 1}}{z} \\ xyz = x + y + z\end{cases}\]
If \(x = \dfrac{\sqrt{a}}{b} , y = c\dfrac{\sqrt{d}}{e} , z = f\sqrt{g}\) satisfy the above system of equations, then find \( (a + b + \ldots + g )\).
- The expression is in simplest terms, meaning that all of the variables are positive integers, \( a, d, g \) are square free and \(c, e \) are coprime.
by
U Z
Let \(a\) and \(b\) be positive integers such that \(a\ge\ b\) and\[\frac{a+1}{b}+\frac{b+1}{a}\]is also a positive integer. Find sum of all possible values of \(a\) which are less than 1000.
by
Kazem Sepehrinia
The system of equations
\[ 4a^4+36a^2b^2+9b^4=20a^2+30b^2-1\]
\[2a^3b+3ab^3=5ab\]
has \(n\) nonnegative (meaning both \(a\) and \(b\) are nonnegative) real solutions. Let these solutions be \((a_1,b_1),(a_2,b_2),\cdots (a_n,b_n)\). The value of the sum
\[\sum_{i=1}^n a_i+b_i\]
can be expressed in the form \(\dfrac{a+b\sqrt{c}}{d}\) where \(\gcd (a,b,d)=1\) and \(c\) is squarefree. Find \(a+b+c+d\).
by
Nathan Ramesh
A positive real number is given. In each move, we can either add \(3\) to it, subtract \(3\) to it, multiply it by \(3\) and divide it by \(3\). The sum of all numbers such that after exactly \(3\) moves, the original number comes back is \(\frac{a}{b}\), where \(a\) and \(b\) are relatively prime positive integers. Find \(a + b\).
by
Zi Song Yeoh
Find the largest possible value of \(x^3+y^3+z^3\) for real \(x,\ y,\ z,\) such that \[ \begin{cases} xyz^2=-64y-128x\\ x^2yz=-32y-32z\\ 3xy^2z=128x-64z \end{cases} \]
by
Calvin Lin