Cos(A±B) Formulae

Trigonometric Identities|Applications|A, B Formulas|Applications|C, D Formulas|Sin & Cos Graphs|Small Angle Approximations|Example Questions|Co- Ordinate Geometry

(Projection Formulae) if a,b,c are the lengths of the sides opposite respectively to the angles A,B,C of a triangle ABC, show that a=b cos C+cos B( ii) b=os A+a cos C( iii )c=a cos B+b cos A

Half Angle Formula of (cos A)/(2)(cos B)/(2)(cos C)/(2)

(a+b)^(2) formula

If sin A=(1)/(sqrt(5)) and sin B=(1)/(sqrt(10)) ,find the values of cos A and cos B .Hence using the formula cos(A+B)=cos A cos B-sin A sin B, show that (A+B)=45^(@).

Prove that formula cos(A-B)=cos A*cos B+sin A*sin Bwith the help of the formula sin(A+B)=sin A*cos B+cos A*sin B

Standard Formula sin(A+B) || sin(A–B) || cos(A+B) || cos(A–B)

Standard Formula sin(A+B) || sin(A–B) || cos(A+B) || cos(A–B)

Standard Formula sin(A+B) || sin(A–B) || cos(A+B) || cos(A–B)