If `tan^2((pi-A)/4)+tan^2((pi-B)/4)+tan^2((pi-C)/4)=1` , then ` A B C` is (A) equilateral (B) isosceles (C) scalene (D) none of these

In triangle ABC, if |[1,1,1], [cot (A/2), cot(B/2), cot(C/2)], [tan(B/2)+tan(C/2), tan(C/2)+ tan(A/2), tan(A/2)+ tan(B/2)]| then the triangle must be (A) Equilateral (B) Isoceless (C) Right Angle (D) none of these

(tan ((pi)/(4) +4))/( tan ((pi)/(4) -x ))= ((1 + tan x )/( 1- tan x )) ^(2)

tan^6(pi/9)-33tan^4(pi/9)+27tan^2(pi/9) is equal to (a)0 (b) sqrt3 (c) 3(d)9

Prove that (1-tan^2(pi/4-A))/(1+tan^2(pi/4-A))=sin2Adot

If alpha=tan^(-1)(tan""(5pi)/(4))andbeta=tan^(-1)(-tan""(2pi)/(3)), then

In Delta ABC if tan(A/2) tan(B/2) + tan(B/2) tan(C/2) = 2/3 then a+c

int_0^oo(x dx)/((1+x)(1+x^2)) is equal to (A) pi/4 (B) pi/2 (C) pi (D) none of these"

Show that int_(0)^((pi)/(2))(tan^(4)x)/(1+tan^(4)x)dx=(pi)/(4)

Prove that tan ((pi)/(4) + theta) tan ((3pi)/(4) + theta) = -1