TRIGONOMETRIC FUNCTIONS Radius AF = 1 = sin 2 A + cos 2 A = sin A cosec A = cos A sec A = tan A cot A Sine A = cos a/cot a = 1/cosec a = cos a tan a = =BC Cosine A = sin a/tan a = 1/sec a = sin a cot a = =AC Tangent A = sin A/cos A = 1/cot A = sin A sec A =FD Cotangent A = cos A/sin A = 1/tan A = cos A cosec A =HG Secant A = tan A/sin A = 1/cos A =AD Cosecant A = cot A/cos A = 1/sin A =AG RIGHT ANGLED TRIANGLES a2 = c2 – b2 b2 = c2 – a2 c2 = a2 + b2 Known Required A B a b c Area a,b tan A = a/b tan B = b/a ab/2 a,c sin A = a/c cos B = a/c a/2 A,a 90o – A a cot A a/sin A (a2 cot A)/2 A,b 90o – A b tan a b/cos A (b2 tan A)/2 A,c 90o – A c sin a c cos A (c2 sin 2 A)/4 OBLIQUE ANGLED TRIANGLES a2 = b2 + c2 – 2 bc cos A b2 = a2 + c2 – 2 ac cos B c2 = a2 + b2 – 2 ab cos C Known Required A B a b c Area a,b,c tan 1/2 A = K/(s-a) tan 1/2 B = K/(a-b) tan 1/2 C = K/(s-c) a,A,B 180 – (A + B) (a sin B)/sin A (a sin C)/sin A a,b,A sin B = (b sin A)/a (b sin C) / sin B a,b,C tan A = (a sin C)/(b – a cos C) (ab sin C)/2
