Using vectors , prove that in a triangle ABC
` a = b cos C + c cos B`
where a,b,c are lengths of the ideas opposite to the angles A,B,C of triangle ABC respectively .

Using vectors , prove that in a triangle ABC a^(2)= b^(2) + c^(2) - 2bc cos A where a,b,c are lengths of the ideas opposite to the angles A,B,C of triangle ABC respectively .

Using vectors , prove that in a triangle ABC a/(sin A) = b/(sin B) = c/(sin C) where a,b,c are lengths of the ideas opposite to the angles A,B,C of triangle ABC respectively .

In any triangle ABC, prove that cosA + cos B + cos C le 3/2

If angle C of triangle ABC is 90^0, then prove that tanA+tanB=(c^2)/(a b) (where, a , b , c , are sides opposite to angles A , B , C , respectively).

Let ABC is be a fixed triangle and P be veriable point in the plane of triangle ABC. Suppose a,b,c are lengths of sides BC,CA,AB opposite to angles A,B,C, respectively. If a(PA)^(2) +b(PB)^(2)+c(PC)^(2) is minimum, then point P with respect to DeltaABC is

If in a triangle ABC, b sin B = c sin C, then the triangle is-

In a triangle ABC, (a+b+c)(b+c-a)=kbc if

In a triangle ABC, if (cos A)/(a) =(cos B)/(b ) =(cos C)/(c) and the side a=2, then the area of the triangle is-

In /_\ABC ,Prove that a cos A + b cos B + c cos C = 2a sin B sin C

In the triangle ABC if (2 cos A)/a + ( cos B)/b + (2 cos C)/c = a/(bc) + b/(ca) find the angle A.