Search results
Results From The WOW.Com Content Network
Pascal's pyramid's first five layers. Each face (orange grid) is Pascal's triangle. Arrows show derivation of two example terms. In mathematics, Pascal's pyramid is a three-dimensional arrangement of the trinomial numbers, which are the coefficients of the trinomial expansion and the trinomial distribution. [1]
The only integer triangle with three rational angles (rational numbers of degrees, or equivalently rational fractions of a full turn) is the equilateral triangle. [2] This is because integer sides imply three rational cosines by the law of cosines , and by Niven's theorem a rational cosine coincides with a rational angle if and only if the ...
One may show by induction that F(n) counts the number of ways that a n × 1 strip of squares may be covered by 2 × 1 and 1 × 1 tiles. On the other hand, if such a tiling uses exactly k of the 2 × 1 tiles, then it uses n − 2 k of the 1 × 1 tiles, and so uses n − k tiles total.
The middle entries of the trinomial triangle 1, 1, 3, 7, 19, 51, 141, 393, 1107, 3139, … (sequence A002426 in the OEIS) were studied by Euler and are known as central trinomial coefficients. The only known prime central trinomial coefficients are 3, 7 and 19 at n = 2, 3 and 4. The -th central trinomial coefficient is given by
In geometry, a Heronian triangle (or Heron triangle) is a triangle whose side lengths a, b, and c and area A are all positive integers. [ 1 ] [ 2 ] Heronian triangles are named after Heron of Alexandria , based on their relation to Heron's formula which Heron demonstrated with the example triangle of sides 13, 14, 15 and area 84 .
Taking L to be the x-axis, the line integral between consecutive vertices (x i,y i) and (x i+1,y i+1) is given by the base times the mean height, namely (x i+1 − x i)(y i + y i+1)/2. The sign of the area is an overall indicator of the direction of traversal, with negative area indicating counterclockwise traversal.
The sum of (,) is 1 + 6 + 6 + 1 = 14, which is the 4th Catalan number, . This sum coincides with the interpretation of Catalan numbers as the number of monotonic paths along the edges of an n × n {\displaystyle n\times n} grid that do not pass above the diagonal.
The Möller–Trumbore ray-triangle intersection algorithm, named after its inventors Tomas Möller and Ben Trumbore, is a fast method for calculating the intersection of a ray and a triangle in three dimensions without needing precomputation of the plane equation of the plane containing the triangle. [1]