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A Linear System Limit
Sequences satisfy , , and
Find and $\lim_{n\to\i…
A Telescoping Tangent Sum
Given , evaluate
An Area Range from a Parallel Chord
The ellipse () is given. A line passes through the origin, and a line parallel to meets the ellipse at two points and…
A Quadratic Form Window
Real numbers satisfy
Find the range of possible values of .
A Diagonal Dot Identity
In quadrilateral , the diagonals satisfy and . Find
\left(\overrightarrow{AB} + \overrightarrow{DC}\right)\cdot\left(\overrightarrow{BC} + \overrightarrow…Powers Two Apart
Find the number of positive integer solutions of
A Rectangle in an Ellipse?
Let be three points on the ellipse (), and let be the origin. Can the quadrilateral be a rectangle? Justif…
Two Solutions of a Mixed Equation
The equation
has exactly two real solutions. Find the range of .
Derivative Symmetries
Differentiable functions on satisfy
and is an even function. Determine, with proof, …
Where to Build the Dock
As shown in the figure, an aquaculture center is located on an island . Two towns and lie on a straight coas…
Growth of a Recursion
Let , , and
1. Prove that there exists with for all . 2. Prov…
A Quadratic-Form Maximum
Real numbers satisfy
Find the maximum value of .
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