(ii) If none of A, B is 0 and `A+B=pi/2`, then `cot A cot B =1`.

(i) If none of A, B is pi/2 and A+B= pi/2 , then tan A tan B =1 .

If A + B= pi/4 , show that (cot A-1) (cot B-1) =2

In a triangle ABC , if 3a = b + c , then cot B/2 cot C/2 =

(i) If tanA-tan B=x and cot B- cot A=y . Prove that cot(A-B)=1/x + 1/y . (ii) If 2 cos A = x+1/x, 2 cos B = y + 1/y , then show that 2 cos (A-B)= x/y+y/x .

if A+ B + C = pi, and cos A = cos B cos C, show that 2 cot B cot C=1.

In a DeltaABC , 2 Delta (cot B + cot C)=

If tan - A tan B = x, cot B - cot A = y prove that cot (A - B) = (1)/(x) + (1)/(y)

If in A B C ,A C is double of A B , then the value of cot(A/2)cot((B-C)/2) is equal to 1/3 (b) -1/3 (c) 3 (d) 1/2

The base B C of A B C is fixed and the vertex A moves, satisfying the condition cot(B/2)+cot(C/2)=2cot(A/2), then (a) b+c=a (b) b+c=2a (c) vertex A moves along a straight line (d) Vertex A moves along an ellipse

Prove that : (cot A + tan B)/ (cot B + tan A) = cot A tan B