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a tst 2013 test
Math2030   11
N 2 hours ago by whwlqkd
Given the sequence $(a_n):   a_1=1, a_2=11$ and $a_{n+2}=a_{n+1}+5a_{n}, n \geq 1$
. Prove that $a_n $not is a perfect square for all $n > 3$.
11 replies
Math2030
May 24, 2025
whwlqkd
2 hours ago
Geometry
Exoticbuttersowo   1
N 3 hours ago by sunken rock
In an isosceles triangle ABC with base AC and interior cevian AM, such that MC = 2 MB, and a point L on AM, such that BLC = 90 degrees and MAC = 42 degrees. Determine LBC.
1 reply
Exoticbuttersowo
Yesterday at 7:28 PM
sunken rock
3 hours ago
Pure algebra problem
lgx57   1
N 3 hours ago by HAL9000sk
If $a_0=5$,$a_n=a_{n-1}+\dfrac{1}{a_{n-1}}$. Let $S=a_{1000}$
Calculate $S$.

PS1: The more precise decimal places there are, the better.(rounded down)
PS2: Please don't use python or C++, or this problem will be very easy.
1 reply
lgx57
6 hours ago
HAL9000sk
3 hours ago
Counting problem
lgx57   1
N 4 hours ago by HAL9000sk
Calculate the number of $n$ that meet the following conditions:
1. $585 \mid n$
2.$0 \sim 7$ appears exactly once in each octal digit of $n$
1 reply
lgx57
6 hours ago
HAL9000sk
4 hours ago
Geometry
Arytva   0
5 hours ago
Let \(ABC\) be an acute triangle, and let its circumcircle be \(\Gamma\). On side \(BC\), pick a point \(D\) (distinct from \(B\) and \(C\)). The lines through \(D\) tangent to \(\Gamma\) (other than \(DA\), if \(A\) lies inside the angle at \(D\)) touch \(\Gamma\) again at points \(E\) and \(F\). Let \(BE\) meet \(AC\) at \(P\), and let \(CF\) meet \(AB\) at \(Q\). Prove that the three lines \(AP\), \(AQ\), and \(EF\) are concurrent.
0 replies
Arytva
5 hours ago
0 replies
Easy Function
Darealzolt   1
N 6 hours ago by alexheinis
Let \( f(x+y) = f(x^2y)\) for all real numbers \(x,y\), hence find the value of \(f(3)\) if \(f(2023)=26\).
1 reply
Darealzolt
6 hours ago
alexheinis
6 hours ago
Spot-It inspired question
alexroberts   1
N Today at 6:25 AM by alexroberts
Oscar bought a set of blank playing cards. He puts stamps on each card such that
1. Each card has $k\geq 4$ different stamps each.
2. Every two cards have exactly one stamp in common.
3. Every stamp is used at least twice.

Show that the maximum number of different stamps $v$ he can use is in the range $$k^2-2k+5 \leq v \leq k^2-k+1$$
1 reply
alexroberts
Wednesday at 8:46 PM
alexroberts
Today at 6:25 AM
Floor of Cube Root
Magdalo   2
N Today at 6:18 AM by RedFireTruck
Find the amount of natural numbers $n<1000$ such that $\lfloor \sqrt[3]{n}\rfloor\mid n$.
2 replies
Magdalo
Jun 2, 2025
RedFireTruck
Today at 6:18 AM
Find the value of m
Darealzolt   2
N Today at 6:13 AM by RedFireTruck
Let \(m\) be a positive integer, such that \(m\) fulfills
\[
\frac{1}{m^2+3m+2}+\frac{1}{m^2+5m+6}+\frac{1}{m^2+7m+12}+\dots +\frac{1}{m^2+15m+56}+\frac{1}{m^2+17m+72} = \frac{8}{33}
\]Hence find the value of \(m\).
2 replies
Darealzolt
Yesterday at 11:38 AM
RedFireTruck
Today at 6:13 AM
common tangents
gasgous   2
N Today at 5:26 AM by gasgous
Find the equations of the common tangents to the circles:$\left(x-1\right)^2+{(y+2)}^2=16$ and $\left(x+2\right)^2+{(y-3)}^2=36$.
2 replies
gasgous
Jun 4, 2025
gasgous
Today at 5:26 AM
arbitrary point on Euler line
sarjinius   1
N Apr 22, 2021 by SerdarBozdag
Let $\triangle ABC$ be an acute triangle with circumcenter $O$ and orthocenter $H$. Suppose that $AB \neq AC$. Let $M$ be an arbitrary point on line segment $OH$. Let $P$ and $Q$ be points on $AB$ and $AC$ respectively such that $MA = MP = MQ$. Prove that the circumcenter of $\triangle MPQ$ lies on the perpendicular bisector of $BC$.
1 reply
sarjinius
Apr 14, 2021
SerdarBozdag
Apr 22, 2021
arbitrary point on Euler line
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sarjinius
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Let $\triangle ABC$ be an acute triangle with circumcenter $O$ and orthocenter $H$. Suppose that $AB \neq AC$. Let $M$ be an arbitrary point on line segment $OH$. Let $P$ and $Q$ be points on $AB$ and $AC$ respectively such that $MA = MP = MQ$. Prove that the circumcenter of $\triangle MPQ$ lies on the perpendicular bisector of $BC$.
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SerdarBozdag
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