Covid19 has spread globally. when the Covid-19 pandemic occurs, schools must be closed or partially opened, which affects teaching and learning. Educational innovations to deal with epidemics such as Covid-19 and other urgent epidemics are very important.Because some areas of mathematics are still incomplete today, this makes current technical tools such as online calculators Wolfram Alfa and Symbolab unable to direct solve certain Solution of triangle problems. This book also pres...

Quarantine for all asymptomatic strategy is incorrect in most high infection Covid-19 countries. Covid-19 surges in Italy (2020) and Taiwan (June 2022) are repeating the same mistakes made in Wuhan (China). This strategy will accumulate more asymptomatic high viral load super-spreaders and cause longer period of high infection. However, China's strict zero-coronavirus strategy is difficult to replicate in other high-infection Omicron countries because it is a costly strategy. Peter Chew's ...

The new covid-19 mutants usually have a higher transmission rate, the maximum positive rate must be lower to ensure that the undetected virus covid-19 carriers are low and the country is controlled. Different countries may face high infection with different covid-19 mutants, Therefore, each country must have a specific maximum positive rate based on its country’s covid-19 mutant. This study will create a general formula to determine the maximum positive rate for each country based on its c...

This book uniquely combines the authors’ personal experiences, deep cultural and professional experience of living and working in Russia and the former USSR, and interest and experience with language and computational analysis, to shed light on a highly contemporary question: what is motivating conflict and unrest in Russia and its surrounding countries? How does Russian government suppression of information manifest in practice today, and how does it fit into the historical cultural patte...