Variational principles play an important role in the formulation of many problems of mathematical physics.变分原理现在许多数学物理的表述中起着重要作用.After studying differential calculus you will be able to solve these mathematical problems....
Pain-killers are very useful in small amounts to bring your temperature down.小剂量的止痛药对于降低体温非常有用。The police are searching for his killers.警方正在搜捕杀害他的凶手。Giant-killers Yeovil became the most successful non-league club in hist...