In any triangle `A B C ,` prove the projection formula`a=b cosC+c cosB` using vector method.

In any triangle A B C , prove that following : (a-b)cosC/2\ = csin((A-B)/2)

In as triangle ABC prove that: cos (A+B)+cosC=0

In any triangle A B C , prove that following: \ \ bcosB+c\ cos\ C="a c o s"(B-C)

In a triangle ABC the expression a cosB cosC+b cosA cosB equals to :

In any triangle A B C , prove that: acos((B-C)/2)=(b+c)sin(A/2)

In any triangle A B C , prove that following : (a+b)/c=(cos((A-B)/2))/(sin(C/2))

In any triangle A B C , prove that following: sin((B-C)/2)=(b-c)/a cos (A/2)

In any triangle A B C prove that: sin((B-C)/2)=((b-c)/a)cosA/2

In any triangle A B C , prove that following: \ a\ (cosB cos C+cos A)=b(cos C\ cos A+cos B)=c(cos A\ cos B+cos C)dot

In any triangle A B C , prove that: \ asin(B-C)+b sin(C-A)+csin(A-B)=0