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Binomial coefficients and Pascal's triangle
Identities, the binomial theorem, and combinatorial proofs.
C(n, k) counts k-subsets, is the coefficient in (a + b)ⁿ, and satisfies Pascal's rule C(n, k) = C(n−1, k−1) + C(n−1, k). Picture it: Pascal's triangle, each entry the sum of the two above. Think it: a combinatorial proof shows two formulas count the same set, no algebra needed.
ਕੰਮ ਉਦਾਹਰਨ · expand (a + b)^6
ਕਦਮ ਦਰ ਕਦਮ
- \left(a + b\right)^{6}
Start from the expression.
- a^{6} + 6 a^{5} b + 15 a^{4} b^{2} + 20 a^{3} b^{3} + 15 a^{2} b^{4} + 6 a b^{5} + b^{6}
Distribute (multiply out) the products.
ਜਵਾਬ ਦਿਓ
ਹੁਣ ਤੁਸੀਂ ਇੱਕ ਸਮੱਸਿਆ ਚੁਣੋ, ਜਾਂ ਆਪਣਾ ਆਪ ਲਿਖੋ ਜਾਂ ਖਿੱਚੋ। ਹਰ ਕਦਮ, ਇੱਕ ਤਸਵੀਰ, ਜਵਾਬ ਜਦੋਂ ਤੱਕ ਤੁਸੀਂ ਪੁੱਛਦੇ ਹੋ, ਲੁਕਿਆ ਰਹਿੰਦਾ ਹੈ।
ਇੱਥੇ ਵਰਤੇ ਨਿਸ਼ਾਨ
ਕਿਸੇ ਵੀ ਨਿਸ਼ਾਨ ਨੂੰ ਦਬਾਉ, ਜਿਸ ਵਿੱਚ ਪੂਰੀ ਪਰਿਭਾਸ਼ਾ, ਇੱਕ ਤਸਵੀਰ ਅਤੇ ਹਰ ਅੱਖਰ ਦਾ ਅਰਥ ਹੈ ।
ਕਿਵੇਂ: Binomial coefficients and Pascal's triangle
- Start from the expression.
- Distribute (multiply out) the products.
ਲੋਕ ਪੁੱਛਦੇ ਹਨ
Permutation or combination?
Ask whether order matters. A lock code is a permutation (order matters); a hand of cards is a combination (it does not).
What is a graph in this sense?
Dots (vertices) joined by lines (edges), not a plot. Road maps, social networks and molecules are graphs; questions like "is there a route" and "how few colours" are graph theory.
ਹੋਰ ਵਿੱਚ Combinatorics & Graph Theory
The counting principlesPigeonhole principle and inclusion, exclusionRecurrences and generating functionsGraphs: vertices, edges, degreesPaths, cycles, trees, Euler and HamiltonColouring and planar graphs