tan(a+4分之派)=2010,得(1+tana)/(1-tana)=2010,可得tana=2009/2011
1/cos2阿尔法=(sin^2a+cos^2a)/(cos^2a-sin^2a)=(1+tana)/(1-tana)=2010
tan2a=2tana/(1-tan^2a)=4040099/4020
1/cos2a+tan2a=2010+4040099/4020