In `Delta ABC` if `5r=2R ` then `cos A+cos B+cos C=`

In any Delta ABC, prove that :a cos A+b cos B+c cos C=2a sin B sin C

In any Delta ABC, show that cos A+ cos B+ cos C = (1+ (r )/(R )).

In a Delta ABC, show that (a cos A+b cos B+ c cos C)/(a+b+c)= (r )/(R )

In a Delta ABC, the value of (a cos A+b cos B+c cos C)/(a+b+c) is equal to

The distance between the circumcentre and orthocenter of a Delta ABC is R sqrt(1-lambda cos A*cos B*cos C), then lambda=

In Delta ABC, show that (1-cos A+cos B+cos C)/(1-cos C+cos A+cos B)=tan((A)/(2))cot((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)/(c cos B+b cos A)=(a^(2)+b^(2)+c^(2))/(2abc)

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)

If in a triangle ABC,3R=4r then cos A+cos B+cosC =