tana+1/tana=9/4,则tan^2+1/sinacosa+1/tan^2a=?
问题描述:
tana+1/tana=9/4,则tan^2+1/sinacosa+1/tan^2a=?
答
∵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