If `A + B + C=pi`, then find the minimum value of `cot^2A + cot^2B + cot^2C`

Let a, b, c , d he real numbers such that a + b+c+d = 10 , then the minimum value of a^2 cot 9^@+b^2 cot 27^@+c^2 cot 63^@+d^2 cot 81^@ is sqrtn ,(n in N) find n.

If b +c =3a , then find the value of cot.(B)/(2)cot.(C)/(2)

if ABC is a triangle and tan(A/2), tan(B/2), tan(C/2) are in H.P. Then find the minimum value of cot(A/2)*cot(C/2)

In a triangle ABC if b+c=3a then find the value of cot(B/2)cot(C/2)

In a triangle ABC if b+c=3a then find the value of cot(B/2)cot(C/2)

In a triangle ABC if b+c=3a then find the value of cot(B/2)cot(C/2)

Find the minimum values of: cot^(2)A+cot^(2)B+ cot ^(2)C where A,B,C are the angles of a triangle.