tana+1/tana=9/4,则tan^2+1/sinacosa+1/tan^2a=?

∵tana+1/tana=9/4
∴tana=1/2.或tana=4
∴tan^2a+1/sinacosa+1/tan^2a
=tan^2a+(sin^2a+cos^2a)/sinacosa+1/tan^2a
=tan^2a+tana+1/tana+1/tan^2a
=1/4+1/2+2+4
=6又3/4
或=16+4+1/4+1/16
=20又5/16