In a triangle ABC with usual notation, if `a+b= 3c`, then `tan (A/2) tan(B/2)` is equal to

If in triangle ABC , with usual notations , a=18,b=24,c=30 , then sin.(A)/(2) is equal to

If in a triangle ABC, b + c = 3a, then tan (B/2)tan(C/2) is equal to

If in a triangle ABC, b + c = 3a, then tan (B/2)tan(C/2) is equal to

In a /_\ABC with usual notations a=3, b=4, c=5 then inradius is equal to

In Delta ABC with usual notation, (c-b cos A)/(a) is equal to

If in a triangle ABC with usual notation, a(a-c)=b^(2)-c^(2) ,then 1572(sin^(2)(pi cos^(2)B)) is equal to

With usual notations, in triangle ABC, a cos (B-C)+b cos (C-A)+c cos(A-B) is equal to

With usual notations,in a triangle ABC,acos(B-C)+b cos(C-A)+c cos(A-B) is equal to

If in a triangle ABC, in the usual notation, 2a cos ((B-C)/(2))=b+c and Be neC . Then the measure of the angle A is