" Whit the heb of vectors,in any "-" that "cos C=(2^(2)+B^(2)-2)/(200)

Prove that, in any triangle ABC, cos C=(a^2+b^2-c^2)/(2ab) .

Prove that, in any triangle ABC, cos B=(c^2+a^2-b^2)/(2ca) .

In any Delta ABC, prove that cos C=(a^(2)+b^(2)-c^(2))/(2ab) with the help of vectors

Prove in any triangle ABC that (i) a(cos B+cos C)=2(b+c) "sin"^(2)(A)/(2) (ii) a(cos C- cosB)= 2(b-c )"cos"^(2)(A)/(2)

In any triangle ABC, then by vectors, prove that : c^2=a^2+b^2-2ab cos C .

In any DelataABC prove that "a(cos C - cos B)=2(b-c)cos"^(2)A/2

For any triangle ABC,prove that a(b cos C-c cos B)=b^(2)-c^(2)

In any Delta ABC, prove that: (cos A)/(b cos C+c cos B)+(cos B)/(c cos A+a cos C)+(cos C)/(a cos B+b cos A)=(a^(2)+b^(2)+c^(2))/(2abc)

In any Delta ABC , prove that cos C = (a^2+b^2-c^2)/(2ab) with the help of vectors