cos[2tan^(-1)((1)/(7))]" equals "

cos(2 tan^(-1)(1/7)) equals: a. "sin"(4cot^(-1)3) b. "sin"(3cot^(-1)4)\ c. "cos"(3cot^(-1)4) d. "cos"(4cos^(-1)4)

The value of cos[2tan^(-1)(-7)] is

(tan^(-1)(sqrt3)-sec^(-1)(-2))/(cosec^(-1)(-sqrt2)+cos^(-1)(-(1)/(2))) is equal to

The value of cos[2 tan^(-1)(-7)] is

Show that: cos(2tan^(-1)((1)/(7)))=sin(4tan^(-1)((1)/(3)))

The value of x satisfying the equation tan^(-1)x + tan^(-1)((2)/(3)) = tan^(-1)((7)/(4)) is equal to

If a=cos (2.tan^(-1).(1)/(7))and b = sin (4.tan^(-1).(1)/(3))