【国立清华大学理科报告】第一种算学物理化学工程 - 国立.pdf
國立清華大學理科告 V no-3
MOULMEIN ROAD,BHANGHAI
Dan Sun where B A aretherootsof thequadraticequation(1,3) ct²+(cd-cd-1)t+d=0.Hence the two sheets of the focal surface coincideif and only if(1,4)(cd+cd-1)²-4ccdd=0.Therefore,if the condition(1,4)is identically satisficd,the systemof differentialequations(1,1)maybeusedforthe study oftheprojecti