Trigonometric Formula:-
Ø Sin A = 1/Cosec A OR Cosec A= 1/Sin A
Ø Cos A = 1/Sec A OR Sec A = 1/ Cos A
Ø Tan A = 1/Cot A OR Cot A = 1/Tan A
Ø Tan A = Sin A/Cos
A OR Cot A = Cos A/Sin A
Sin 2A = 2Sin A Cos A = 2 Tan A /1+Tan 2A
Ø Cos 2A = Cos 2A – Sin 2A = 1 – 2Sin 2A = 2 Cos 2A -1 = 1- Tan 2A/1+ Tan 2A
Ø Tan 2A = 2 Tan A/1-Tan 2A
Sin 3A = 3Sin A – 4Sin3A
Cos 3A = 4 Cos 3A – 3 Cos A
Tan 3A = 3Tan A – Tan3A/1- 3Tan2 A
Sin (A+B) = Sin A. Cos B + Cos A. Sin B
Ø Sin (A-B) = Sin A. Cos B - Cos A. Sin B
Ø Cos (A+B) = Cos A. Cos B - Sin A. Sin B
Ø Cos (A-B) = Cos A. Cos B + Sin A. Sin B
Ø Tan (A+B) = Tan A + Tan B/1- Tan A Tan B
Ø Tan (A-B) = Tan A - Tan B/1+ Tan A Tan B
Ø Cot (A+B) = Cot B. Cot A -1/ Cot B +Cot A
Ø Cot (A-B) = Cot B. Cot A +1/ Cot B -Cot A
Sin C + Sin D = 2 Sin (C+D/2) .Cos ( C-D/2)
Sin C - Sin D = 2 Cos (C+D/2) . Sin ( C-D/2)
Cos C + Cos D = 2 Cos (C+D/2) .Cos ( C-D/2)Cos C - Cos D = 2 Sin (C+D/2) . Sin ( D-C/2)
Trigonometric Equations:-
v Sin 2A + Cos 2A = 1
v Sec 2A - Tan 2A = 1
v Cosec2 A – Cot2 A = 1
Angles:-
Sin (90-A) = Cos A
Cos (90-A) = Sin A
Tan (90-A) = Cot A
Cot (90-A) = Tan A
Sec (90-A) = Cosec A
Cosec (90-A) = Sec A





