tana=-22
则(seca)^2=1+(tana)^2=485
(cosa)^2=1/(seca)^2=1/485
(sina)^2-3sinacosa+1
=(cosa)^2[(tana)^2-3tana+(seca)^2]
=(1/485)*(484+66+485)
=1035/485
=207/97