Prove the questions :
`1-tan.(A)/(2)tan.(B)/(2) = (2c)/((a+b+c))`

In any triangle A B C , prove that following : c/(a+b)=(1-tan(A/2)tan(B/2))/(1+tan(A/2)tan(B/2))

In any triangle A B C , prove that following : c/(a+b)=(1-tan(A/2)tan(B/2))/(1+tan(A/2)tan(B/2))

If A+B+C=pi , prove that : tan( A/2) tan (B/2) + tan (B/2 )tan (C/2)+ tan( C/2) tan (A/2) =1

In any triangle A B C , prove that following : c/(a-b)=(tan(A/2)+tan(B/2))/(tan(A/2)-tan(B/2))

In any DeltaABC , prove that (i) tan""(B-C)/2=(b-c)/(b+c)cot""A/2 . (ii) If angleB=90^(@) , prove that tan(A/2)=sqrt(((b-c)/(b+c))) . (iii) If angleC=90^(@) , prove that tan((A−B)/2)/tan((A+B)/2)=(a-b)/(a+b) .

In a triangle Delta ABC , prove the following : (tan A//2)/((a-b)(a-c))+(tan B//2)/((b-c)(b-a))+(tan C//2)/((c-a)(c-b)) = (1)/(Delta)

If in Delta ABC, tan.(A)/(2) = (5)/(6) and tan.( C)/(2)= (2)/(5) , then prove that a, b, and c are in A.P.

In any Delta ABC , prove that : ((a-b)/c) = (tan (A/2) - tan (B/2))/(tan (A/2) + tan (B/2)

Let A, B and C are the angles of a plain triangle and tan(A/2)=1/3,tan(B/2)=2/3 .then tan(C/2) is equal to

Prove that : tan [(pi)/(4) + (1)/(2) cos^(-1)""(a)/(b)] + tan[(pi)/(4) - (1)/(2) cos^(-1)""(a)/(b)] = (2b)/(a) .