Category
Trigonometry
Identities, transformations, and angles that refuse to simplify.
Trigonometry sits between algebra and geometry, and contest problems exploit both sides of it. Identities compress an ugly expression; the unit circle turns angle chasing into arithmetic.
You will find identity manipulation, equations over restricted domains, sums of trigonometric series, and problems where the trigonometric form is a disguise for something much simpler underneath.
Latest problems
37 problems
Collapsing a Linear Combination
1417
11
Cosines in a Triangle
1333
10
Counting Solutions to a Trig Equation
1333
10
Equal Tangent and Cotangent
1500
11
Geometric Sequence of Trig Expressions
1417
9
Matching a Tripled Angle
1250
7
Series of Arccotangents
1172
24
Sum of Sine of Threes
1583
10
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