Category Archives: Proof

Euclid’s proof of infinite number of primes and bigger primes

Posted on July 7, 2023 by Sumant Sumant

Sometimes students confuse that if we use the product of first n consecutive primes and add 1 we are bound to get a prime number however this is not true. The proof by contradiction only says that the number obtained … Continue reading →

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If the sum of the digits of a four digit number is divisible by 3, then the four-digit number is also divisible by 3 (Direct Proof)

Posted on June 4, 2023 by Sumant Sumant

If the sum of the digits of a four digit number is divisible by 3, then the four-digit number is also divisible by 3

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Why Variance formula is E(x^2)-(E(x))^2 ?

Posted on June 1, 2023 by Sumant Sumant
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Derivation of distance of plane from the origin

Posted on April 19, 2023 by Sumant Sumant
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IB Math SL Paper 1, 6 May, 2022 Question 3 (Proof 3 divides sum of consecutive number)

Posted on April 8, 2023 by Sumant Sumant
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Why Chromatic Index of complete graph is odd ?

Posted on April 7, 2023 by Sumant Sumant
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Chromatic Index of an odd regular graph

Posted on April 6, 2023 by Sumant Sumant
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Every Walk contains a Path

Posted on April 2, 2023 by Sumant Sumant
Posted in Graph Theory, Mathematical Induction, Proof, Proof by Cases | Tagged | Leave a comment

Why there are only 5 Platonic Solids ?

Posted on April 1, 2023 by Sumant Sumant
Posted in Combinatorics, Graph Theory, Proof | Tagged | Leave a comment

Expectation and Variance of Poisson Distribution

Posted on February 21, 2023 by Sumant Sumant
Posted in Probability, Proof, Statistics | Tagged | Leave a comment