Trigonometric Identities. (i) sin2 + cos2 =1 (ii) 1 + tan2 = sec2 (iii) 1 +cot2 = cosec2 Trigonometric Ratios of some specific angles. 0o 30o 45o 60o 90o sin 0 ½ 1/2 3/2 1 cos 1 3/2 1/2 1/2 0 tan 0 1/3 1 3 Not defined cot Not 3 1 1/3 0 defined sec 1 2/3 2 2 Not defined cosec Not 2 2 2/3 1 defined Trigonometric ratios of complementary angles. sin (90o - ) = cos cos (90o - ) = sin tan (90o - ) = cot cot (90o - ) = tan sec (90o - ) = cosec cosec (90o - ) = sec
Trigonometric Identities. (i) sin2 + cos2 =1 (ii) 1 + tan2 = sec2 (iii) 1 +cot2 = cosec2 Trigonometric Ratios of some specific angles. 0o 30o 45o 60o 90o sin 0 ½ 1/2 3/2 1 cos 1 3/2 1/2 1/2 0 tan 0 1/3 1 3 Not defined cot Not defined 3 1 1/3 0 sec 1 2/3 2 2 Not defined cosec Not defined 2 2 2/3 1 Trigonometric ratios of complementary angles. sin (90o - ) = cos cos (90o - ) = sin tan (90o - ) = cot cot (90o - ) = tan sec (90o - ) = cosec cosec (90o - ) = sec