関連ワード:  if cos a=(2)/(3) then 2 sec^(2)a+2 tan^(2)a-7 is equal to    relationship between sec^2 and tan^2    2 sin a/2 cos a/2 is equal to    how to prove 1+tan^2=sec^2  
結果 : if cos a=(2)/(3) then 2 sec^(2)a+2 tan^(2)a-7 is equal to