已知sina=2根号5/5求tan(a+π)+sin(5π/2+a)/cos(5π/2-a)

已知sina=2根号5/5求tan(a+π)+sin(5π/2+a)/cos(5π/2-a)
已知sina=2根号5/5求tan(a+π)+sin(5π/2+a)/cos(5π/2-a)

已知sina=2根号5/5求tan(a+π)+sin(5π/2+a)/cos(5π/2-a)
原式
=tana+cosa/sina
=1/(sinacosa)
∵sina=2√5/5,
∴cosa=±√5/5
∴原式=±5/2