関連ワード:  sec^2 = tan^2 - 1 identity    sec 2x tan 2x 1 identity    sec 2 theta tan 2 theta 1 identity    sec^2 tan^2 identity    tan^2 rule    does sec^2 = tan    relationship between sec^2 and tan^2  
結果 : sec^2 = tan^2 - 1 identity