If `(3-tan^2(pi/7))/(1-tan^2(pi/7))=kcos(pi/7)` then the value of `k` is (a)1 (b) 2 (c) 3 (d) 4

If (3-"tan"^(2)(pi)/(7))/(1-"tan"^(2)(pi)/(7))="k cos" (pi)/(7) then the value of k is

If (3-tan^(2)((pi)/(7)))/(1-tan^(2)((pi)/(7)))=k cos((pi)/(7)) then the value 1-tan^(2)((pi)/(7)) of k is (a) (b)2(c)3(d)4

2tan^(-1)(tan((7pi)/6))

If [(cos(2pi)/7,-sin(2pi)/7),(sin(2pi)/7, cos(2pi)/7)]^k=[(1,0 ),(0 ,1)] , then the least positive integral value of k is (a) 3 (b) 4 (c) 6 (d) 7

If tan^(2)(pi-A)/4 + tan^(2)(pi-B)/2 + tan^(2) (pi-C)/4=1 , then triangleABC is:

cos (cos^-1 cos((8pi)/7) +tan^-1 tan(8pi/7)) has the value equal to -

prove that 2(tan^(-1)1)/(3)+(tan^(-1)1)/(7)=(pi)/(4)

cos (cos^-1 cos((8pi)/7) +tan^-1 tan((8pi)/7)) has the value equal to -