Question

The angle a is such that seca+tana=2 show that seca-tana=1/2

Answer 1

seca+tana=2

inverting both sides

1/seca+tana =1/2

(seca^2-tana^2=1)

(seca+tana)(seca-tana)/seca+tana=1/2

therefore

seca-tana=1/2