Prove that in `triangle ABC, 2cos A cosB cos Cle(1)/(4)`.

In a triangle ABC, cos A+cos B+cos C=

If A+B+C=π Prove that in triangle ABC, sin A+sin B+Cle(3sqrt(3))/(2)

Prove that in triangle A B C ,cos^2A+cos^2B-cos^2C=1-2sinAsinBcosCdot

In triangle ABC, if cos A + cos B + cos C = (7)/(4), " then " (R)/(r) is equal to

In a triangle ABC cosA+cosB+cosC<=k then k=

In a triangle ABC, a (b cos C - c cos B) =

If in a triangle ABC, 2 (cos A)/(a) + (cos B)/(b) +2 (cos C)/(c) = (a)/(bc) + b/(ca) then the value of the angle A is

Statement I: If in a triangle ABC, sin ^(2) A+sin ^(2)B+sin ^(2)C=2, then one of the angles must be 90^(@). Statement II: In any triangle ABC cos 2A+ cos 2B+cos 2C=-1-4 cos A cos B cos C

Using vector method prove that in any triangle ABC a^2=b^2+c^2-2bc cos A .

In a triangle ABC, sin A- cos B = Cos C , then angle B is